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Political Science Research and Methods Vol 6, No. 3, 527–548 July 2018
© The European Political Science Association, 2016 doi:10.1017/psrm.2016.18

Strategic Ambiguity of Party Positions in Multi-Party

Competition*
THOMAS BRÄUNINGER AND NATHALIE GIGER

P
arty competition is largely about making policy promises to voters. We argue that the
clarity of the expressed policy position may be equally important. If blurred messages
toward different audiences and therefore ambiguous positions can attract votes from
different groups, parties have incentives to present ambiguous rather than clear-cut policy
platforms. We present a formal model of multi-party competition with stochastic voting where
party leaders make strategic choices on both the position and the level of ambiguity of their
platforms. Leaders respond to the demands of two principals, the general public and party core
constituencies. We derive two hypothesis on the location and ambiguity of party platforms and
provide initial tests of these hypotheses in a comparative setting in 14 Western European
democracies gathering data on voter and party left-right positions from Eurobarometer surveys
and electoral manifestos. Ambiguity of party profiles is estimated using a variant of
Wordscores on a newly established data set of electoral manifestos. We find that platforms
become more ambiguous as the preferences of the two principals diverge. Our findings imply
that ambiguity can be a winning strategy for parties, especially in settings with strong
partisan lines.

W
hen following election campaigns, both journalists and scholars frequently observe
that it is impossible to precisely pin down the position of the competing parties or
candidates on relevant issues. Parties and candidates often seem reluctant to say
precisely what they stand for and what policies they promise to implement once they are elected
into office. Such obfuscation or ambiguity is well described for the US context (Shepsle 1972;
Page 1976; Bartels 1986; Aldrich 1995; Meirowitz 2005; Milita, Ryan and Simas 2014). Some
even consider it a “stylized fact” about American elections that “candidates becloud their
policies in a fog of ambiguity” (Downs 1957). Vagueness of party positions is also observed in
multi-party systems, but when and why vagueness exists in such contexts is more complex and
not well understood. In fact, most theoretical work on ambiguity focuses on two-party
competition. In this study, we advance the literature on party ambiguity by presenting a formal
model of multi-party competition with ambiguous party positioning. Confronting two
observable implications of the model with data on 14 European party systems over 25 years
provides support for our theoretical account.
It is widely accepted that ambiguity is seen as being the result of strategic behavior by parties.
If targeted messages toward specific groups and therefore ambiguous positions can attract votes

* Thomas Bräuninger is a Professor of Political Economy in the Department of Political Science, University of
Mannheim, A5, 6 68131 Mannheim (Thomas.Braeuninger@uni-mannheim.de). Nathalie Giger is an Assistant
Professor in the Department of Political Science and International Relations, University of Geneva, 40 boulevard
du Pont d’Arve, CH-1211 Genève 4 (Nathalie.Giger@unige.ch). Previous and quite different versions of this
paper were presented at the Annual Conference of the European Political Science Association in Edinburgh in
2014 and various seminars. The authors are particularly indebted to Michael Bechtel, Bill Heller, Gijs Schumacher
and the reviewers for useful comments and suggestions. Funding from the European Science Foundation (HumVIB
EUROSCORES) and the Deutsche Forschungsgemeinschaft (INST 34/96) is gratefully acknowledged. Replication
materials are available at the Havard Dataverse at http://dx.doi.org/10.7910/DVN/GK9VCH. The alphabetical
ordering of the authors’ names reflects their equal contributions to this paper. To view supplementary material for this
article, please visit http://dx.doi.org/10.1017/psrm.2016.18.
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528 BRÄUNINGER AND GIGER

from different groups, parties have incentives to present ambiguous rather than clear-cut policy
platforms. In fact, there is an evolving empirical literature suggesting that ambiguous policy
platforms can help parties win votes (Rovny 2012; Somer-Topcu 2015).
Although the assertion that parties strategically obfuscate their programmatic positions by
blurring their position is electorally rewarding seems innocent, there is less consensus on the
mechanism of how ambiguity is used strategically by parties and candidates in electoral
competition. In an early contribution, Shepsle (1972) finds that ambiguity is a beneficial
strategy in two-candidate competition only if a majority of voters are risk-acceptant in some
environment of the median voter. Under such circumstances, an incumbent (unambiguously)
positioned at the median can be defeated by a challenger announcing a lottery of positions in
that environment with expectation at the median. A different perspective is offered by Page
(1976) and more recently by Rovny (2012), who argue that ambiguity eventually means
avoiding talking about divisive issues. Candidates highlight and take a clear stance on
consensus issues while blurring positions on issues where the constituency is divided to attract
broader support or to not deter voters. Later works have discussed related mechanisms that
result in ambiguous position taking. Some focus on the unwillingness of candidates to reveal
their true position (Alesina and Cukierman 1990), either to secure flexibility in office (Aragones
and Neeman 2000) or to be able to adhere to a different position after primaries reveal the
preferences of the electorate (Meirowitz 2005). Further work emphasizes the uncertainty about
the median voter position as possible source of candidate ambiguity (Glazer 1990) or context-
dependent voting (Callander and Wilson 2008).
Although all these arguments are plausible in the context of two-party systems, little is known
about whether and how they extend to or work in multi-party systems. We do not know whether
and when intentional ambiguity by agents is an equilibrium strategy in a competitive envir-
onment where not one but all agents can take a clear stance or blur their position. Even less is
known about the prevalence of ambiguous strategies in real-world multi-party systems beyond
anecdotal or case-study evidence. The goal of this paper is precisely to answer these questions.
We present a model of multi-party competition with ambiguous position taking by parties. In
line with previous works, we argue that position taking is only one aspect of strategic party
competition. The clarity of the expressed position or the amount of ambiguity surrounding this
position are equally important in the competition for electoral support. More specifically, we
posit that in multi-party competition, party elites make strategic choices on both the position and
the level of ambiguity of their platforms. Our point of departure is the more recent literature on
multi-party competition that has offered a general model of elections where parties’ positional
strategies are dependent not only on voters’ perception of party positions but also on the support
of party activists (Schofield and Miller 2007). In the argument, originally suggested by Aldrich
(1983), activists provide valuable resources to their candidate with the resources varying
depending on the distance of the candidate’s position. As a result, party elites accommodate the
claims of policy-motivated, non-centrist activists (see also Aldrich 1983; Strøm 1990; Ware
1992; Adams, Merrill and Grofman 2005; Adams and Somer-Topcu 2009). A related argument
underlies the class of models where candidates or parties have policy preferences (Wittman
1977; Calvert 1985; Adams, Merrill and Grofman 2005) so that they adhere to divergent
platforms that gear toward their core constituencies.1 In both arguments, the positions taken by
party elites incorporate the preferences of policy-motivated activists and, for most cases, predict
divergence of party positions in multi-party competition rather than convergence at the median

1
The extensive theoretical work includes Cox (1984), Chappell and Keech (1986), Groseclose (2001),
Duggan and Fey (2005), and Roemer (2006).
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Strategic Ambiguity of Party Positions 529

or mean voter (Schofield and Sened 2006). This is also what we observe empirically in
European multi-party systems.
The novelty of the model presented in this paper is to allow party elites to strategically choose
ambiguous policy platforms in the pursuit of balancing the electoral consequences with the
necessity of preserving the support of party activists. The notion of party elites who serve two
competing principals, voters and party activists, is captured by the assumption that party leaders
strive for both government and party office. In multi-party competition, the objective to attain
government office can be proxied by the motivation to maximize vote shares in general
elections.2 At the same time, party leaders strive for party office, that is, they seek to get
re-elected by party members or activists in a national party conference. Of course, parties differ
in the rules and practices of how they hold their leaders accountable. Party leaders may also
differ in their time horizons and the compromises between the two objectives they are willing to
make. What is important here is the notion that there is a set of party members or activists with
the ability to displace the party leader (crystallized in the notion of the “decisive party
member”).
We think of a party platform (or any other campaign message) as a piece of information that
voters use to update their prior beliefs on the position of the sender of the message, the party
leader. The more specific the information, the more any receiver can learn from the platform and
the more similar will be the posterior beliefs of groups of voters that had different initial beliefs.
An ambiguous position or platform, on the other hand, provides little information on the party
leader that voters and party activists could use to update their prior beliefs. As, in the end, party
leaders are also party members that have been working for and within the party for many years,
we assume that the expectations or prior beliefs of party members about their leaders’ type is
both more specific and biased (toward the party) than those of the general electorate. If party
members differ in their policy preferences from the general electorate, leaders face a trade-off
when drafting their electoral platform or manifesto (Strøm and Müller 1999). If the initial beliefs
of the general electorate and party members diverge, providing an ambiguous platform can be a
winning strategy. Our model suggests that formulating ambiguous policy positions can actually
help leaders to do the splits.
We characterize local Nash equilibria (LNE) of the model and perform Monte Carlo
simulation to derive two hypotheses on the location and ambiguity of party platforms. First, we
expect that leaders draft platforms that are located between the decisive party member and the
some “weighted” electoral mean. Second, leaders use more ambiguous platforms the more
non-centrist the party, and hence the equilibrium platform of the party, is. Even in multi-party
settings, leaders of extreme parties have incentives to get close to the electoral mean but they are
pulled away by party activists. Offering an ambiguous platform can help in getting the
support of regular voters and party members—even though both are risk-averse.
We provide an initial test of these hypotheses in a comparative setting in 14 Western
European democracies gathering data on voter and party left-right positions from
Eurobarometer surveys and political texts.3 Ambiguity of party profiles is estimated using a
variant of Wordscores (Laver, Benoit and Garry 2003) on a newly established data set of
electoral manifestos. Estimating ambiguity from political texts provides a very direct measure of
2
This is the standard assumption in canonical models of multi-party competition. A more complex model
would include post-electoral bargaining (and legislative policy-making) to allow party leaders to condition their
strategies on expected coalitions (and voter choices on policy outcomes).
3
Our empirical focus on the left-right dimension carries the advantage that this is most important dimension
in electoral competition; not talking about or ignoring an issue as a form of being ambiguous is thus not a viable
option for any political party.
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530 BRÄUNINGER AND GIGER

positional ambiguity that is not conflated with other types of (voter-based) uncertainty.4 Using
this novel measure of ambiguity we find evidence that ambiguous position taking is widespread
and systematic across European parties. Consistent with our expectation we see that platforms
become more ambiguous as the preferences of the two principals, the voting public and the
party core constituency, diverge. In sum, our findings imply that ambiguity could be a winning
strategy for parties, especially in settings with strong partisan lines.
This paper proceeds as follows. In the next section, we present the formal model and derive
empirical expectations from a Monte Carlo simulation. We then discuss the data and the
methodology used to arrive at measures of the location of party platforms, their ambiguity and
the decisive party member. The third section presents results of the statistical analysis. We
conclude by exploring implications of the findings for party competition and voting behavior
and discussing future avenues for research.

A MODEL OF STRATEGIC AMBIGUITY

The party competition model presented here is an extension of existing models of multi-party
competition that assume office-seeking parties and policy-seeking voters with proximity-based
evaluation functions with stochastic components (Lin, Enelow and Dorussen 1999; Adams,
Merrill and Grofman 2005; Schofield 2006). Where we differ is the assumption on parties as
unitary actors. The key idea underlying our model is to distinguish party leaders from their rank-
and-file. Party leaders therefore have not one but two objectives. They seek control over
government office and they want to retain their party office. They benefit from party office if
they get re-elected by the party rank-and-file, whereas, in multi-party competition in large
districts, the government office ambition is best served when they maximize pluralities in
general (Hinich and Ordeshook 1970). We therefore use the relative vote share as a reasonable
proxy for the likelihood of getting into government office and assume that the goals are related
in a linear, additive manner.5

Assumptions
Formally, each party leader j is characterized by an objective function that maximizes a linear
combination of the expected utilities from getting elected into government and party office
(where the utilities for getting elected and not getting into government and party office are
normalized to 1 and 0):
uj ð^zÞ = p1j + αp2j : (1)

The probability p1j is the expected vote share of party j, p2j the probability that the party leader
stays in party office, α > 0 a weighing parameter that we assume to be constant across parties.
We assume a set of voters N = {1, … , n} with generic voter i having a canonical quadratic
random utility function with ideal point xi 2 X where X is a closed interval in R. There is a set
of P parties. Any party j has a pivotal party member with ideal point xmj (and quadratic random
4
Uncertainty is here referred to as a psychological state in which voters are unsure about party positions.
Thus, uncertainty does not only arise due to ambiguous statements but also when voters fail to receive or
correctly interpret campaign messages for other, idiosyncratic reasons. Contrary to this, we define ambiguity as
an attribute of party position taking.
5
In a more complex setup, the likelihood of retaining party office could be related to the party leader’s
success in the general election, or, vice versa, the expected benefits of government office may also be conditional
on the likelihood that the party leader gets re-elected.
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Strategic Ambiguity of Party Positions 531

utility functions) who has the decisive vote on the party convention or similarly that selects the
party leadership. Party leaders choose a policy platform to declare ^zj . We depart from previous
work on party competition by allowing party leaders to present an ambiguous party platform
rather than a single, unique policy position to their constituencies. We think of a platform as a
random variable that is realized after the election. To keep things as simple pffiffiffi as possible,
pffiffiffi  we
assume that the platform ^zj has a uniform distribution on the interval zj  3σ j ; zj + 3σ j . The
strategy of a party leader thus involves choosing a platform mean zj and a platform variance σ 2j
rather than a single and unambiguous point. Let ^z = ð^z1 ; ¼; ^zP Þ be a generic vector of these
party platforms.
As noted above, we assume that voters have quite unspecific expectations and evaluate party
platforms where they are likely given the information they receive. We can think of voters with
uninformative, uniformly distributed priors on X that are updated via Bayes’ rule using the
information ^zj so that their posterior belief about the party position is just ^zj . Therefore, each
voter is described by the vector of expected putilities
ffiffiffi ð^zffiffiÞ=ðv
vip ffi  i1 ð^z1 Þ; ¼; vip ð^zp ÞÞ where, for the
density fj of the uniform distribution U zj  3σ j ; zj + 3σ j
ð
vij ð^zj Þ= ððxi yÞ2 + ϵj Þfj ðyÞdy = σ 2j ðxi zj Þ2 + ϵj :

The first term, vij ð^zj Þ=σ 2j ðxi zj Þ2 , is the observable part of the utility that decreases in the
distance between the voter ideal point and the expected party position. As voters are risk-averse,
utility is decreasing whenever the variance of the platform increases. The second term, εj, is the
stochastic component of the utility function. Following previous work on stochastic voting
models, we assume that any εj has a type I extreme value distribution. With this assumption, the
probability that voter i votes for party j is given by
exp½vij ðxi ; ^zj Þ
ρij ð^zÞ= :
P
P

exp½vik ðxi ; ^zk Þ
k=1
Pn
The expected vote share of party j is p1j ð^zÞ= 1n ρij ð^zÞ and the marginal changes in the expected
vote share are given by i=1

∂p1j 1 X n
= 2ðxi zj Þðρij ρ2ij Þ;
∂zj n i=1
(2)
∂p1j 1 X n
= 2σ j ðρij ρij Þ:
2
∂σ j n i=1

We point to three noteworthy implications: first, the first derivative is positive whenever zj is
smaller than what we henceforth refer to as the “weighted electoral mean” of party j (Schofield
2007):
P
ðρij ρ2ij Þxi
EMj = P : (3)
ðρij ρ2ij Þ
Thus, the electoral support of a party increases when the platform mean moves toward the
weighted
P electoral mean. We should emphasize that unlike the conventional “electoral mean”,
j is specific to each party and varies with the platform profile ^ z as all the ρij are
1
n x i , EM
functions of ^z. Whatsoever, the weighted electoral mean represents the electoral pull on the
party, that is, the direction where additional votes can be gained. Second, the derivative of the
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532 BRÄUNINGER AND GIGER

vote share with respect to the platform variance is strictly negative, which is a straightforward
implication of the assumption that voters are risk-averse. Third, if party leaders were concerned
about winning government office, only, that is α = 0, the unique Nash equilibrium would be the
strategy profile where each party leader would present an unambiguous, zero-variance platform
at the mean voter position. This is the stochastic mean voter theorem (Lin, Enelow and
Dorussen 1999) for a one-dimensional policy space.
As we argued above, party members certainly have more specific expectations on where their
party leaders stand as compared with the more diffuse expectations of non-party members. Still,
party members may be prepared to accept policy compromises of their leaders as a means to
attain government office. They will thus use the information that is contained in the platform to
update their beliefs about likely policies the party leader will pursue once she is elected into
government. We can think of the prior expectation of the decisive party member as a random
variable which we assume
pffiffiffi to be,
pffiffiffito make things as simple as possible again, uniformly
distributed over ½xmj  3ω; xmj + 3ω where xmj is the position of the decisive party member
(aka the median party member) and ω is the variance of the prior.6
Updating a uniform prior distribution (the initial belief) with uniformly distributed new
information (the platform) is straightforward. As long as party leaders are interested in both
government and party office, the support intervals will intersect and the posterior simply is a
uniformly distributed random variable over the intersection of the two supports. As we know
that in any equilibrium, the platform mean of any party is located between the weighted
electoral mean and the decisive party member (see Proposition in the supplementary material),
the posterior belief of the decisive party member mj is given by
pffiffiffi pffiffiffi
Uðxmj  3ω; zj + 3σ j Þ if EMj ≤ zj ;
pffiffiffi pffiffiffi
Uðzj  3σ; xmj + 3ωÞ if zj < EMj :
pffiffiffi
These posterior distributions have means μj = 12 ðzj + xmj ± 3ðstÞÞ and variances
zj xm
τj = σ +2 ω ± 2pffiffi3 j where ± refers to the two cases EMj ≶ xmj. The decisive party member’s
expected utility of the party leader then simply is v0j ðμj ; τj Þ=τ2j ðxmj μj Þ2 + ϵj .
How likely is it that a party leader proposing a platform that does not perfectly match the
prior expectations of her party constituency actually gets re-elected? Although we do not know
the exact offer or promise of the party leader’s intra-party challenger to the rank-and-file,
assuming that the decisive party member’s evaluation of the challenger is given by some
exogenous 0 vcj + ϵcj , the re-appointment probability of the party leader is given by
exp½v 
p2j = exp½v0   + jexp½vc . The marginal changes (and that is what we are really interested in) then are
j j

∂p2j 1 pffiffiffi pffiffiffi

= ð  2 3σ j ± 3ω + 2ðxmj zj ÞÞðp2j p22j Þ;
∂zj 3
  (4)
∂p2j 2ðxmj zj Þ
= 2σ j + ω ± pffiffiffi ðp2j p22j Þ;
∂σ j 3

where we again save notation and write ± for the cases EMj ≶ xmj.
6
One might think of w as possibly related to intra-party heterogeneity or the existence of factions. This is
beyond our concern here, nor do we have reliable data on the prior variance, so that we assume that it is constant
across parties. We also note that, strictly speaking, decisive party members are a subset of the group of voters.
We ignore this complication in the model setup as the added value would be minimal.
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Strategic Ambiguity of Party Positions 533

Equilibria
At a Nash equilibrium of the model, the partial derivatives of uj, the party leaders’ utility
function, with respect to zj and σj are 0 for all P parties. That is
∂uj ∂p1j ∂p2j
= +α = 0;
∂zj ∂zj ∂zj
(5)
∂uj ∂p1j ∂p2j
= +α = 0:
∂σ j ∂σ j ∂σ j
Substituting the above equation for Equations 2 and 4, and solving for zj and σj gives for all j:
P  pffiffiffi pffiffiffi 
3 ðρij ρ2ij Þxi + αnðp2j p22j Þ xmj  3σ j ± 12 3ω
zj = P ;
3 ðρij ρ2ij Þ + αnðp2j p22j Þ

αnðp2j p22j Þ ± p1ffiffi3 ðxmj zj Þ + 12 ω

σj = P : ð6Þ
ðρij ρ2ij Þ + αnðp2j p22j Þ
Unfortunately, there is no simple closed-form solution to these equations as all probabilities, the
ρ’s and p’s, are also functions of z and σ.
So what can we learn from these equations? We note that the additive “probability” terms in
both denominators (the “ðρij ρ2ij Þ”, the “αnðp2j p22j Þ” and the “αnðp2j p22j Þ” terms) also show
up in the nominators suggesting that they serve as some sort of weight for the constitutive,
“distance” terms in the nominators. To get a better intuition, we substitute Equation 6 for the
definition
P of the weighted electoral mean, EMj, from Equation 3 and use the definition
ðρ ρ2 Þ
λ= αnðp2jijp2ijÞ . We can then rewrite Equation 6 as follows:
2j pffiffiffi pffiffiffi
3λEMj + ðxmj  3σ j ± 12 3ωÞ
zj = ;
3λ + 1
pffiffiffi (7)
pffiffiffi ± ðxmj zj Þ + 12 3ω
3σ j = ;
λ+1
which gives a more sensible idea of the equilibrium strategies. The first equation suggests that
party leaders
pffiffiffi propose
pffiffiffi platforms, the means of which are weighted averages of EMj and
xmj  3σ j ± 12 3ω. In other words, the platform means balance the pull of the general
electorate and that of the party members. The weights of the convex combination are just
3λ/(3λ + 1) and 1/(3λ + 1). The secondpffiffiequation
ffi suggests that, in the same vein, the level of
ambiguity of the platform (note that p3ffiffiσffi j is just half the length of the platform) is a convex
combination of 0 and ± ðxmj zj Þ + 12 3ω. The weights here are λ/(λ + 1) and 1/(λ + 1).
Put simply, while we know what the equilibrium looks like—the platform mean is a convex
combination of the weighted electoral mean and the party activist position—there is no way to
write down the equilibrium in plain numbers as the weighted electoral mean, EMj, is itself a
function of the individual voting probabilities ρij—that is, it is an endogenous variable.
Thus, the recursive nature of the above equations precludes making straightforward and simple
statements on the expected location of the party leaders’ platforms. However, we establish
conditions for the existence and uniqueness of LNE, which we provide in a theorem in the
supplementary material. Moreover, we can use Monte Carlo techniques to numerically simulate
the equilibrium model which will provide us with testable hypotheses about the nature of party
competition with ambiguous messages. This is what we do next.
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534 BRÄUNINGER AND GIGER

−2 −1 0 1 2 −2 −1 0 1 2

−2 −1 0 1 2 −2 −1 0 1 2

Fig. 1. Monte Carlo simulation of ambiguity model of party competition

Note: Numerical equilibria of four exemplary runs of the model described in the main text (with n = 1000
voter ideal points sampled from N(0, 1), and decisive party members xmj sampled from N(0, 1)). Panels show
voter p distribution
ffiffiffi pas
ffiffiffi well as, for each party, the prior belief of the decisive party member
½xmj  15 3; xmj + 15 3 (intervalpwith
ffiffiffi filled
pffiffifficircle), the weighted electoral mean EMj (hollow circle) and the
party equilibrium platform ½zj  3σ; zj + 3σ (interval with star).

Monte Carlo Simulation

We set up a Monte Carlo simulation to come up with expectations on party platforms in equi-
librium. In particular, we shall see that platform variances are ceteris paribus larger the more
distant the equilibrium mean position is from the weighted electoral mean of the party. To this
end, we implement an iterative approximation algorithm using the λ contraction T from the
Theorem in the supplementary material. While we neither know the number of LNE nor the size
of the environment U where unique local equilibria exist, contraction T guarantees that the
iterative approximation algorithm converges to an LNE in the environment of the starting point.7
More specifically, we run a series of 100 scenarios. In any of these scenarios, the ideal points
xi’s of 1000 voters are sampled from a normal distribution with mean 0 and unit variance, a
party system with P 2 f3; 5; 7g parties (size of the party system sampled from a uniform
distribution) is set up with positions of decisive party members, xmj , also sampled from N(0, 1).
For each scenario, the approximation algorithm was set up with ten different starting values
where values for the zj’s were sampled from Uð0; xmj Þ and starting values for σp j’sffiffiffi are drawn
from a uniform distribution over the interval from 0 to j xmj starting valueðzj Þ j = 3 + 12 ω. We
fix ω to 0.2. With this initial setup unique LNE exist in all 100 scenarios.
The results for four exemplary scenarios are shown in Figure 1. We point out three notable
observations. First, the mean of any equilibrium platform (zj, represented by a star) is located
between the decisive party member (xmj , filled circle) and the party’s weighted electoral mean
(EMj, hollow circle), which follows from what we found above. Second, the panels suggest that

7
The supplementary material for this article provide the R code for the simulation.
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Strategic Ambiguity of Party Positions 535

platform ambiguity (σj) is a function of the spatial location of the platform mean and/or the
party’s weighted electoral mean. When the decisive party member is close to the weighted
electoral mean and/or close to the mean of the voter distribution, the equilibrium platform is less
ambiguous. Parties at the extremes of the party system, in particular when the distance between
decisive party member and electoral mean is large, present more ambiguous party platforms in
equilibrium. Third, we note that the party’s weighted electoral means—which represent the
electoral pull on the party leaders—are centrally located.
Finally, we run a series of regressions for the 100 scenarios and find that the level of
ambiguity is linearly related to the distance between the weighted electoral mean and the
platform mean. Although this provides us with a quite specific hypothesis (“the level ambiguity
of a party platform increases in j EMj xmj j ”), there is no way to test it in such a specific way as
the weighted electoral mean is an unobservable variable.
We therefore seek to provide an initial test of our theory of ambiguous platforms by testing
two weaker hypotheses. Although we do not know the exact location of the weighted electoral
mean EMj and therefore cannot derive hypotheses directly, the simulation results suggest that
the EMj’s are more centrist than the decisive party members, in many cases they are even close
to the (unweighted) electoral mean (which is close to 0 in the simulation panels of Figure 1).
This provides two hypotheses on party competition in a world with ambiguous party platforms.
As the model considers a world where party leaders can choose both a ideological position (or
platform mean) and a level of ambiguity, the first concerns the location of party platform means
whereas the second refers to platform ambiguity:

HYPOTHESIS 1: The mean of the platform of a party is more centrally located than the position of
the decisive member of that party.

HYPOTHESIS 2: The relationship between party platform means and party platforms variances is
U-shaped, that is, platform variances are smaller the more centrally located the
platform means.

We now seek to test these expectations with real-world data.

DATA AND MEASUREMENT

To test our expectations, we need a measure of platform ambiguity, or, more generally, the
heterogeneity of positions taken by or within a party. The literature offers several ways to arrive
at such a measure. Let us quickly outline what these alternatives are before we elaborate in more
details on the method chosen for the empirical analysis of party systems in 14 countries in this
paper. One option to measure intra-party heterogeneity—which has been used most extensively
in the literature—is to look at roll-call votes (e.g., Sieberer 2006; Ensley 2011; Tavits 2011).
There are at least two reasons why measures of diversity based on roll-call votes are problematic
for the purpose of our study. First, roll-call votes may properly reflect the cohesion of MPs’
preferences but they may also suppress existing heterogeneity in the presence of disciplinary
measures by the party leadership or anticipated negative consequences of dissenting behavior
such as career concerns of individual MPs or the loss of government office (e.g., Ceron 2012).
This is particularly relevant in parliamentary democracies. Given that roll calls are hardly
random samples of the total of votes called (Carrubba, Gabel and Hug 2008), any intra-party
heterogeneity measure based on roll-call votes is likely to be downward biased. Second, our
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536 BRÄUNINGER AND GIGER

argument focuses on the electoral arena. Our model links promises made by the party leadership
to the preferences of voters and of the party rank-and-file—we make no presumptions as to how
electoral promises map into actual party behavior.
A second option to derive measures of party policy ambiguity is to make use of expert
surveys (e.g., Rovny 2012; Greene and Haber 2015). Here, experts are either asked directly after
their perceived level of dissent within parties or heterogeneity is proxied by the variation in
party policy positions perceived by the experts. The latter obviously is a rough proxy, only.
Variation in perceived positions of a party may indicate intra-party heterogeneity when experts
refer to different party factions with different views. They may also reflect the uncertainty in the
point estimate when experts simply have no clue as to what the true position of a (minor)
political party is. As with most expert surveys, a drawback of the approach is that we have
infrequent observations over time. This makes the use of this type of data infeasible if we are
interested in examining processes and trends over time.8
Other scholars have constructed measures of ambiguity from electoral survey data where
either indirect measures of uncertainty of candidate positions have been derived from patterns of
“don’t know” responses or the variation in perceived party placements across all respondents
(Campbell 1983; Bartels 1986; Gill 2005). As pointed out by Bartels (1986) and Tomz and van
Houweling (2009), there is no straightforward connection between individual-level uncertainty
and population-wide variability of political positions. A wide distribution of perceptions of
policy positions does not equal an ambiguous position, as even if all voters were uncertain about
a candidate’s position but had exactly the same (biased) expectation, standard deviations or
entropy scores would overestimate the certainty of the candidate or party position. Even more
relevant in our context is the fact that voter’s uncertainty about a party position is only indirectly
connected to the ambiguity of party positions as announced by the parties. Uncertainty arises
not only when candidates or parties make ambiguous statements, but also when voters fail to
receive the message, interpret it wrongly or are apathetic toward the political statement. So,
while perceptual voter data are useful for exploring electoral consequences of uncertainty in
party positions (see e.g., Dahlberg 2009; Somer-Topcu 2015), our argument focuses on strategic
positioning of parties and for this purpose perceptual measures of party positions are of
little use.
We choose a different approach and rely on information derived from political text to
generate a measure of platform ambiguity.9 Electoral manifestos are specifically drafted for the
public but contain original, undistorted communication by the party itself. This makes this type
of document of special value to measure not only party positions but also party platform
variance. We acknowledge that our measure has limitations as well. First, we cannot capture
ambiguity in policy positions if a party decides to remain silent on the topic instead of issuing a
position (for a discussion of various ambiguity strategies, see Milita, Ryan and Simas 2014;
Somer-Topcu 2015). Although this might pose a serious problem if one were interested in a
single issue, it is less relevant here as we measure positions and ambiguity at the aggregate level
of a left-right ideological scale. Parties cannot afford to be silent on all issues. Second, we may
underestimate ambiguity to the extent that party elites appeal to different groups with “mixed
signals”, for instance, by drafting a leftist manifesto to please party activists but communicating

8
The Chapell Hill expert survey is a notable exception in this respect with a question directly addressed at
the certainty of the issue placement but it is focused on European Integration and therefore of no use for
this study.
9
Milita, Ryan and Simas (2014) also use political text. They (hand-)code candidate statements on campaign
websites to measure ambiguity for two specific topics.
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Strategic Ambiguity of Party Positions 537

more liberal positions to business leaders. In sum, these deficiencies do not weight out the
central advantage of our measure, namely to capture direct communication by political parties.
Recently, much work have used election manifestos to estimate party positions in spatial
models using automated text analysis (Laver, Benoit and Garry 2003; Monroe and Schrodt
2008; Slapin and Proksch 2008; Quinn et al. 2010; Lowe et al. 2011). An advantage of utilizing
election manifestos is that data are—more or less—readily available and allow to trace party
positions over a longer period of time. A large range of election manifestos is accessible through
the open access archive (www.polidoc.net) where more than 1000 manifestos from 18 countries
between 1980 and today are available (Benoit, Bräuninger and Debus 2009). We use data for
Austria, Belgium, Denmark, Finland, France, Germany, Ireland, Italy, Luxembourg, the
Netherlands, Portugal, Spain and the United Kingdom. In the empirical analysis, we have 59
single party-systems-in-an-election-year with a total of 321 parties. A list of these parties is
shown in the supplementary material for this article.
We use an automated text analysis approach that allows us to estimate policy-specific party
positions as well as a measure of the ambiguity of these policy positions over time and for a
wide range of countries.10 More specifically, we build on the Wordscores approach (Laver,
Benoit and Garry 2003; Lowe 2008). The basic idea of this technique is to compare the
frequency distribution of words from different texts and to estimate the policy-area-specific
position of a text on the basis of the differences in the share of used words within a given set of
political documents. Wordscores compares the relative word frequency of a text whose pro-
grammatic position is known to the word distribution of a text of the same character whose
position is unknown. Laver, Benoit and Garry (2003, 314–5) refer to these two types of
documents as “reference texts” and “virgin texts”, respectively.
The key assumption behind Wordscores is that political actors do not use words randomly.
Instead, to send “ideological signals” (Pappi and Shikano 2004) in their election manifestos
parties will use some words more often and others less often or even never. The intuition behind
the Wordscores approach then is the following: every word in a political text indicates a
position on a given scale. The average position of all words in a text thus marks the position of
the party. Given this setup, we argue, the dispersion of the positions of individual words has a
straightforward interpretation. It carries information about positions taken within the party
platform. If, for instance, a text simultaneously contains “rightist” words, that is words asso-
ciated with a right-wing ideology, but also “leftist” words, that is words used signaling a left
ideology, this pattern can be interpreted as an ambiguous position taking. This is exactly what
we do here.11 Formally, suppose that w is the vector of relative word frequencies of an election
manifesto (virgin text) in the k-dimensional universe of all reference text words and ξ is the
vector of word positions (the “Wordscores” from the reference texts). We then use the standard
deviation of the word positions as a measure for the level of positional ambiguity:
vffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
u k
uX
σξ = t wi ðξi μÞ2
i=1

P
where μ = wi ξi is the position (or textscore) of the manifesto. Note that σξ is different from
whatpLaver,
ffiffiffiffi Benoit and Garry (2003) refer to as the standard error of the position estimate, or
σ ξ = N (N is the number of scored words). The standard error reflects the uncertainty
10
For a similar approach based on the Wordfish algorithm, see Lo, Proksch and Slapin (2016).
11
Note that our measure thus captures one specific form of ambiguity, namely issuing left and right positions
simultaneously. For other forms of broad-appeal strategies, see Somer-Topcu (2015).
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538 BRÄUNINGER AND GIGER

standard deviation of party platform (logged)

−1

−2

−3

−4

−5
2 4 6 8 10
mean of party platform

Fig. 2. Scatterplot of party platform means and party platform ambiguity for 321 parties in 59 party
system-elections
Note: The solid line shows the Loess curve, fitted with smoothing parameter α = 0.7 and a polynomial
degree of λ = 2. The dotted lines show the limits of the 95 percent confidence band.

associated with the estimate of the (mean) text position, whereas the standard deviation reflects
the diversity of positions within the manifesto. In terms of our model, we identify the platform
mean by μ and the platform variance by σ 2ξ .
It is worth emphasizing that the selection of the set of reference texts is probably the most
crucial decision taken by the researcher in this type of analysis (Laver, Benoit and Garry 2003).
When the texts to be analyzed are manifestos, the most natural candidates for reference texts are
other manifestos that address similar issues. These documents are similar in terms of the
structure of the text, syntax, terminology and the set of words used. For the purpose of this
paper, we use election manifestos of the year 2002, the last year in our sample, as reference text
(2001 or 2003 depending on the election timing in the countries under study).12 Reference
scores are taken from the Comparative Manifesto Project (CMP) (Budge et al. 2001; Klinge-
mann et al. 2006). For the analyses, we have rescaled the CMP positions on the left-right
(“RILE”) dimension from the −100 to +100 scale used by CMP to the 1–10 scale that is
customarily used in survey research.
To summarize, we estimate the two key variables of interest from party manifestos using the
Wordscores method. The first variable is the mean position of the electoral platform of a
political party on the left-right scale, the second variable is the ambiguity of the platform that we
operationalize by the dispersion of Wordscores in a given text. Among those parties with the
largest ambiguity in our sample are the Conservative People’s Party in Denmark, the Centre
Union in Italy in 1996, whereas those with the lowest ambiguity scores are the Italian Green
Federation in 1992 and the Finnish Centre Party in 1995. Figure 2 provides a first glance into
the possible relationship between party platform means and platform ambiguity.13 As the
scatterplot implies, ambiguity is on average larger, the more extreme party platforms are.
To test our theoretical expectations, data on the voter distribution are derived from the
Eurobarometer surveys that provide information on ~1000 individuals in each member state of

12
Note that our results are robust against the specification of the first year of our sample (1980) as the point of
reference. The share of scored words that is the share of words that are included in the estimation of the mean and
standard deviation is larger for the 2002 specification though.
13
As this variable (platform standard deviation) is highly skewed we use its natural log which considerably
improves the normality.
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Strategic Ambiguity of Party Positions 539

the European Union at one point in time (Schmitt and Scholz 2005). One of the survey
questions asks the respondents to place themselves on a 1–10 left-right ideological scale. To test
our first hypothesis, we need to know the spatial location of the party activists or the decisive
party member. The proxy that we use is the conventional mean of the self-placements of the
party supporters for each party in a given year. In detail, we rely on the vote intention in
combination with the left-right self-placement question. The position of the decisive party
member is calculated as the mean left-right self-placement for all respondents who indicated
that they would support the party in the upcoming parliamentary elections (see also Ezrow et al.
2011). We should stress that this measure is a proxy only, as we do not have reliable infor-
mation on the exact position of active party members. In fact, the Eurobarometer survey does
not include such information and there is no other cross-national source that captures party
member positions over time.
As a consequence of the standardization used by Wordscores, the estimated party position are
on (roughly) the same 1–10 scale as the reference scores. Voter and party measures thus refer to
the same left-right dimension and are on a similar 1–10 scale which allows for meaningful
comparisons of voter and party positions and ambiguities.
A multivariate, multilevel linear regression model is specified to test the second hypothesis.
To account for heterogeneity across national party systems and variation over time, we specify a
two-level mixed model with the higher level being the national party system at a point in time.14
We allow the slopes of the coefficients to vary according to this context and also these random
effects to be correlated (which is of particular importance when specifying quadratic terms, see
Gelman and Hill 2007): more specifically, our model reads as follows:
logðσ ξ; ij Þ = β0j + β1ij zij + β2ij z2ij + Xij β3ij + ϵij ;

β0j = γ 0 + δ0ij ; β1ij = γ 1 + δ1ij ; β2ij = γ 2 + δ2ij ;

ðδ0ij ; δ1ij ; δ2ij Þ  N3 ð0; ΨÞ; ϵij  Nð0; σ 2e Þ;

where σij and zij are the platform standard deviation and the platform mean of party-at-election-
time i in country j. The δj is the random-effect coefficient for country j with covariance matrix Ψ
assumed to be constant across countries. The statistical model also includes a series of controls,
X. A first control refers to characteristics of the election program. Election manifestos differ
widely in length and as the size of the vocabulary used in a text may vary with the length of the
text, the variance of the ideological signals send by these words may be smaller in shorter texts.
We therefore add a control for the length of the program. Initial analyses suggest that the largest
proportion of variance in the dependent variable in the models presented below is captured by
the log of the inverse of the number of words used in a manifesto. We refer to this as the
wordcount. A second set of controls refers to the relative position of a party in the party system
of a country. More specifically, we control for the size of a party to reflect the relative weight of
a party in party competition. Party size is the vote share a party received in the national election
at the point in time under question. Second, the recent literature has put a lot of emphasis on a
presumably different logic of party competition for niche and mainstream parties (e.g., Meguid
2005; Adams et al. 2006; Ezrow et al. 2011). We therefore add an identifier for niche party
status.15 Government party indicates whether the party has been in government or in opposition
14
We split the Belgian data into a French-speaking Walloon and a Dutch-speaking Flemish party system as
Wordscores’ bag-of-words approach works with one language only.
15
The dummy variable takes the value of 1 if a party belongs to the communist, green or nationalist party
family, which is standard procedure in this literature. Operationalizing niche parties without the Greens yields no
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540 BRÄUNINGER AND GIGER

at the time the party manifesto had been drafted. In addition, we add a control for the available
space around a party (distance to the closest next party) to account for the fact that with little
space available, parties could become less ambiguous.

EMPIRICAL RESULTS

We consider party manifestos as bundles of ideological signals that are directed toward at least
two audiences, the general electorate and the party activists. Both groups differ in their stance or
position on specific policy issues and thus party elites that seek both government participation
and party leadership will seek to send targeted messages to either. Although each audience may
also be targeted via specific communication channels, party manifestos summarize these diverse
ideological signals resulting in more or less clear-cut political statements. In multi-party
competition, when parties represent constituencies with distinct interests, party leaders may
have different incentives to be ambiguous. This is what our theoretical model predicts.
We found that in equilibrium, party platform means (zj) are located between the weighted
electoral mean of the party (EMj) and the decisive party member (xmj ). On the empirical front,
while we have a reasonable proxy for the position of party members, the location of the weighted
electoral mean of the party is not readily measurable. Recall that EMj is the weighted mean voter
position where the weights are determined by the probabilities with which individuals cast votes
for each party (see Equation 3). We simply do not have sufficient information on individual
voting behavior in our data to estimate these probabilities. We know, however, that the weighted
electoral mean is centrally located. For this reason, in equilibrium, the platform mean will be
more centrally located than the decisive party member. This is our first hypothesis.
To test this expectation we run a simple linear regression analysis of the party platform means
on the positions of the decisive party members. As the argument refers to all parties of one
specific party system in a given year and country, we set up a regression model with varying
slopes and intercepts. As an initial step we center both variables at the position of the
unweighted mean voter in each party system-election which gives us a rough proxy of the center
of the space. The expectation then is that the regression coefficient for the position of the
decisive party member is smaller than 1 while the intercept is close to 0. We find strong
supporting evidence for Hypothesis 1. As Table 1 shows the average slope or “fixed effect” is as
small as 0.319 with a small variance of 0.032 of the random effect.
The formal model also provides us with a second hypothesis on the strategic choice of party
platform ambiguity. Based on the findings of the Monte Carlo simulation, we expect that the
relationship between party platform means and party platform variances is U-shaped
(Hypothesis 2), that is, parties in the “middle” of the party system ceteris paribus have more
distinct positions than parties more at the extremes of the party system.
In Table 2, we report estimates for three models to test the second hypothesis. The three
models differ in the complexity of the covariates considered. In column 1, we present estimates
for a basic model specification that includes the party position, the squared party position and
the wordcount control. Column 2 reports estimates for a model that includes the same covariates
plus further controls for the status of the party in the party system. Column 3 tests for some
further covariates which slightly reduces the number of observations. The upper part of the table
reports fixed effects, the lower the various random terms.

(F’note continued)
substantially different results than what is reported below. In addition, we employ a recently proposed
amendment that takes the share of the manifesto devoted to left-right issues as indicator for niche status (see
Somer-Topcu 2015).
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Strategic Ambiguity of Party Positions 541

TABLE 1 The Effect of the Position of the Decisive Party Member (xmj ) on the Mean of the
Party Platform (zj)
Variables Model 1 (Parameter (SE))
Fixed-effect coefficients
Intercept −0.057
(0.081)
Decisive party member 0.319***
(0.037)
Random-effect coefficients
Var(Intercept) 0.288
Var(Decisive party member) 0.032
Cov(Intercept, Decisive party member) 0.032
Var(Residual) 0.465
AIC 798.9
BIC 821.5
Log likelihood −393.5
N obs. 321
N groups 59

Note: Estimates and standard errors for parameters of a multilevel model that includes party system-election
varying intercepts and slopes.
***p < 0.001, **p < 0.05, *p < 0.1 (two-tailed).

Overall, the results indicate that the relationship between platform means and platform
ambiguities is U-shaped. Although the quadratic term is positive and significant, it is a weak
criterion as the relationship might be convex but monotone over the range of relevant platform
means (Lind and Mehlum 2010). Rather a U-shape is implied by the condition
β1 + 2β2 xl < 0 < β1 + 2β2 xr for a reasonable interval ½xl ; xr  of platform means. We adopt a
conservative approach and test the combined null hypothesis that either β1 + 2β2 xl ≥ 0 or
β1 + 2β2 xr ≤ 0 for the interquartile range of platform means (4.7, 5.9) of the entire sample. The
slopes are −0.033, 0.032 and −0.032 and the null hypothesis can be rejected with p = 0.002. In
other words, there is strong evidence that the relationship between platform means and platform
ambiguity is U-shaped in the empirical range of platform means.
Although most controls have a significant influence on our dependent variable, they do not
weaken the theoretically interesting relationship between party positions and their ambiguity, the
results remain stable. The random terms show considerable variation between the party system-
elections, not only in terms of intercepts (Var(Constant)) but also in terms of the strength of the
U-shape. The control variables perform as expected if they reach significance at all. Longer
manifestos are in tendency less ambiguous and parties in government draft slightly more precise
manifestos than opposition parties. One might argue that what government parties promise is
more rooted in reality or more constraint by the status quo than what the opposition proposes. We
also find that election manifestos of niche parties are slightly more ambiguous than those of
mainstream parties—a finding that reflects the different nature of party competition faced by these
parties. If we operationalize niche parties in a different, more precise manner (the share of the
manifesto devoted to left-right topics), the effect loses its significance. A further control variable
tabs into the questions of party system compactness: do parties without close neighboring
competitors issue broader, more ambiguous platforms? We therefore include a variable that
measure the minimal distance to the next competitor. The estimate is positive and significant but
the effect is small. Considering that our main findings remain stable even when including these
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542 BRÄUNINGER AND GIGER

TABLE 2 The Effect of the Platform Mean on the Ambiguity of the Platform
Model 1 Model 2 Model 3
Variables (Parameter (SE)) (Parameter (SE)) (Parameter (SE))
Fixed-effect coefficients
Intercept 1.864*** 1.586*** 1.434***
(0.138) (0.145) (0.135)
Platform mean −0.331*** −0.243*** −0.179***
(0.051) (0.053) (0.045)
Platform mean squared 0.032*** 0.025*** 0.018***
(0.005) (0.005) (0.004)
Wordcount 0.487*** 0.486*** 0.484***
(0.004) (0.004) (0.004)
Party vote share −0.000 −0.000
(0.000) (0.000)
Government party −0.015** −0.020***
(0.007) (0.007)
Niche party 0.038***
(0.009)
Niche party (share left-right) 0.009
(0.011)
Distance to closest competitor 0.033**
(0.013)
Random-effect coefficients
Var(Intercept) 0.392 0.406 0.294
Var(Platform mean) 0.072 0.069 0.038
Var(Platform mean squared) 0.001 0.001 0.000
Cov(Intercept, Platform mean) −0.128 −0.127 −0.067
Cov(Intercept, Platform mean squared) 0.010 0.010 0.005
Cov(Platform mean, Platform mean squared) −0.006 −0.006 −0.003
Var(Residual) 0.003 0.002 0.002
AIC −562.208 −558.019 −456.661
BIC −520.722 −505.306 −401.408
Log likelihood 292.104 293.010 243.331
N obs. 321 319 294
N groups 59 59 59

Note: The dependent variable is logðσ ξ Þ. Estimates and standard errors for parameters of multilevel models that
include party system-election varying intercepts and slopes.
***p < 0.01, **p < 0.05, *p < 0.1 (two-tailed).

additional controls we are confident that our results are not driven by the fact that centrist parties
have less space available and are therefore less ambiguous.
Interpreting parameter estimates in multilevel models can be cumbersome. As both intercept
and slopes vary by party system-election in our models, only focusing on estimated average
coefficients (commonly referred to as “fixed” effects in multilevel modeling) tells us little about
differences in the U-shaped relationship between countries or party systems. Figure 3 therefore
shows predicted ambiguity based on the estimated coefficients from Model 1 in each group.
More specifically, we combine the average coefficients with group-level errors to compute
coefficients at the group level and use these intercepts and slopes to predict the ambiguity of
party platforms for each party system-election. The figure shows that the relationship between
platform means and ambiguity is U-shaped as expected. There are a small number of groups
where there is no discernible relationship (e.g., Denmark 1987 and 1988) and even a few
instances where the relationship is slightly inverse U-shaped (e.g., Italy 1983), but these are rare
exceptions.
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Strategic Ambiguity of Party Positions 543

Swe 1998 Den 1981 Den 1984 Den 1987 Den 1988 Den 1990 Den 1994

Den 1998 Fin 1995 Fin 1999 Net 1981 Net 1982 Net 1986 Net 1989

Net 1994 Net 1998 Lux 1984 Lux 1989 Fra 1981 Fra 1986 Fra 1993

Fra 1997 Ita 1983 Ita 1987 Ita 1992 Ita 1994 Ita 1996 Spa 1989

Spa 1993 Spa 1996 Spa 2000 Por 1985 Por 1987 Por 1999 Ger 1980

Ger 1983 Ger 1987 Ger 1990 Ger 1994 Ger 1998 Aus 1995 Aus 1999

UK 1983 UK 1987 Ire 1982 Ire 1987 Ire 1989 Ire 1992 Ire 1997

BeW 1985 BeW 1987 BeW 1991 BeW 1999 BeF 1981 BeF 1985 BeF 1987

BeF 1991 BeF 1995 BeF 1999 −1

−5
2.5 7.5

Fig. 3. Relationship between party platform means (z, displayed on the horizontal axis) and party platform
ambiguity (logðσ ξ Þ, displayed on the vertical axis) for 59 party system-elections
Note: The lines show predicted platform ambiguity based on Model 1 from Table 2. The theoretical
expectation is to find U-shaped regression lines. Swe = Sweden, Den = Denmark, Fin = Finland, Net = the
Netherlands, Lux = Luxembourg, Fra = France, Ita = Italy, Spa = Spain, Por = Portugal, Ger =
Germany, Aus = Austria, UK = United Kingdom, Ire = Ireland, BeW = Belgium (Walloon),
BeF = Belgium (Flanders).

Remarkable is also that the absolute level of ambiguity differs considerably across groups, or,
more precisely, across countries. Such cross-national variations in ambiguity levels are not the
focus of this study but certainly worth further exploration in future work. Can these differences
be attributed to political culture differences or is it simply the language that makes manifestos
more or less ambiguous? Important for this study is, however, that position and ambiguity data
are comparable within a single country at least as platform measures for all parties in one
country are obtained from one and only one estimation. This is exactly why we estimate mixed
effects models where the parameters of interest, the coefficients for the party position and the
squared party position, can vary across party system-elections.
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544 BRÄUNINGER AND GIGER

Finally, one might wonder whether the platform means and standard deviations are inde-
pendent as, by definition, the variance is a function of the mean. Clearly, the “population” of
Wordscores a text is generated from is not normal but has a limited range so that the relation
between mean and variance is unknown (Neyman 1926). To test the null hypothesis that the
standard deviation is a convex function of the mean, merely as a result of the way we measure
the two quantities, we perform a simple simulation test. To this end, we generate hypothetical
manifestos for each party taking random samples of words from the set of reference text words
in the respective country (manifestos have a length of 1000 words). We then calculate platform
means and standard deviations for these texts, run the first model and test for a U-shaped
relation between platform means and the dependent variable. We do this 100 times and find no
single incidence where the null hypothesis of no U-shaped relation could be rejected.

CONCLUSION

In election campaigns, ambiguity of actors’ positions is a frequent observation. Political parties

and candidates often do not articulate their position in a clear-cut manner but remain vague in
what they stand for and what policies they want to implement once in office. In this study, we
offer two advances to the current literature on positional ambiguity of political actors. First, we
contribute to the theoretical literature on positional ambiguity presenting a formal model of
multi-party competition with ambiguous party positioning. We posit that parties make strategic
choices on both the position and the level of ambiguity of their platforms. The central intuition
is that party leaders use programmatic ambiguity to bridge the demands of their two principals,
the general electorate and party activists.
Second, utilizing a new, more direct measure of party ambiguity that is derived from parties’
programmatic statements in electoral manifestos rather than voter perception, and drawing on
empirical material from 14 West European democracies, this study shows that the programmatic
ambiguity of parties in fact varies in a systematic way. This variation is systematically related to
their position vis-à-vis their principals, namely voters and party activists. Positional ambiguity
of electoral manifestos is especially widespread for more extreme parties, so exactly when these
two principals disagree, that is, different demands for position taking exist.
Such behavior can be seen as a variant of party responsiveness where a party does not (or not
only) adapt its policy position in response to voter interests but reacts by adapting the width of
its policy stances. Hence, our focus on party ambiguity adds another twist to the more general
literature on representation. As ambiguity opens up opportunities for parties to be—seemingly
—responsive to their constituencies, we may have to reconsider the quality of (policy)
representation in Europe.
Although the fact that parties do react vis-à-vis their principals on multiple dimensions
can be seen as a positive sign for the working of representation and democracy more broadly,
some note of caution is also warranted. Ambiguous positions of parties make it more
difficult for voters to identify the party closest to their own interests and thus to act according to
the representational ideal. Thus, too much positional ambiguity potentially becomes a threat for
the functioning of electoral democracy. On the other hand, the present study provides
evidence that the ambiguity of party positions is not random but within strict spatial
limits. Further, it is limited to those parties that face clearly defined trade-offs in their position
taking.
Our theoretical model as well as the empirical evidence suggests that more centrist parties
display the lowest levels of positional ambiguity—all else being equal. This may seem sur-
prising to some political observers as these parties, often deemed catch-all parties, reportedly
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Strategic Ambiguity of Party Positions 545

appeal to a broad spectrum of voters which might make their communication less precise.
However, as our study shows, talking about a broad range of things does not necessarily mean
blurring your ideological profile that we measure on the left-right dimension. We believe that
our focus on a direct measure of positional ambiguity is an advantage in this respect as it allows
distinguishing voters’ perceptions from actual party stances.
A second important finding of this study is that, vice versa, more extreme parties on the
left-right dimension have higher levels of positional ambiguity. These results nicely
complement previous work on non-centrist parties suggesting that smaller, more extreme parties
have incentives to highlight their (more clear cut) positions on single, specific issues
(Shepsle 1972; de Vries and Hobolt 2012; de Vries and Marks 2012). If this is correct, our
analysis suggests that clear-cut positions on specific issues may well go along with a blurred
position on the general ideological dimension. Extending our theoretical and empirical
work to a multidimensional space might thus be a promising way to get more leverage on the
strategic incentives for parties to present more or less ambiguous positions on several
dimensions.
Another interesting avenue for future research opens up when combining our results with the
recent finding by Ezrow, Homola and Tavits (2014) that extreme parties are more easily
positioned by voters and thus perceived to be less ambiguous than more centrist parties.
Exploring this mismatch between the ambiguity of the party program and the perception of
ambiguity by voters could be worthwhile.

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