VALIDITY
Validity is the extent to which a test measures what it claims to measure. 1 It is vital for a test to be valid
in order for the results to be accurately applied and interpreted. Psychological assessment is an
important part of both experimental research and clinical treatment. One of the greatest concerns when
creating a psychological test is whether or not it actually measures what we think it is measuring.
For example, a test might be designed to measure a stable personality trait but instead, it measures
transitory emotions generated by situational or environmental conditions. A valid test ensures that the
results are an accurate reflection of the dimension undergoing assessment.
Validity isn’t determined by a single statistic, but by a body of research that demonstrates the
relationship between the test and the behavior it is intended to measure. There are four types of
validity.
Content Validity
When a test has content validity, the items on the test represent the entire range of possible items the
test should cover.3 Individual test questions may be drawn from a large pool of items that cover a broad
range of topics.
In some instances where a test measures a trait that is difficult to define, an expert judge may rate each
item’s relevance. Because each judge bases their rating on opinion, two independent judges rate the
test separately. Items that are rated as strongly relevant by both judges will be included in the final test.
Criterion-Related Validity
A test is said to have criterion-related validity when it has demonstrated its effectiveness in predicting
criteria, or indicators, of a construct.
For example, when an employer hires new employees, they will examine different criteria that could
predict whether or not a prospective hire will be a good fit for a job. People who do well on a test may
be more likely to do well at a job, while people with a low score on a test will do poorly at that job.
There are two different types of criterion validity: concurrent and predictive.
Concurrent Validity
Concurrent validity occurs when criterion measures are obtained at the same time as test scores,
indicating the ability of test scores to estimate an individual’s current state. 5 For example, on a test that
measures levels of depression, the test would be said to have concurrent validity if it measured the
current levels of depression experienced by the test taker.
Predictive Validity
Predictive validity is when the criterion measures are obtained at a time after the test. 6 Examples of
tests with predictive validity are career or aptitude tests, which are helpful in determining who is likely
to succeed or fail in certain subjects or occupations.
Construct Validity
A test has construct validity if it demonstrates an association between the test scores and the prediction
of a theoretical trait.7 Intelligence tests are one example of measurement instruments that should have
construct validity. A valid intelligence test should be able to accurately measure the construct
of intelligence rather than other characteristics, such as memory or education level.
Essentially, construct validity looks at whether a test covers the full range of behaviors that make up the
construct being measured. The procedure here is to identify necessary tasks to perform a job like typing,
design, or physical ability.
In order to demonstrate the construct validity of a selection procedure, the behaviors demonstrated in
the selection should be a representative sample of the behaviors of the job.
Face Validity
Face validity is one of the most basic measures of validity. Essentially, researchers are simply taking the
validity of the test at face value by looking at whether it appears to measure the target variable.8 On a
measure of happiness, for example, the test would be said to have face validity if it appeared to actually
measure levels of happiness.
Obviously, face validity only means that the test looks like it works. It does not mean that the test has
been proven to work. However, if the measure seems to be valid at this point, researchers may
investigate further in order to determine whether the test is valid and should be used in the future.
A survey asking people which political candidate they plan to vote for would be said to have high face
validity, while a complex test used as part of a psychological experiment that looks at a variety of values,
characteristics, and behaviors might be said to have low face validity because the exact purpose of the
test is not immediately clear, particularly to the participants.
Reliability vs. Validity
While validity examines how well a test measures what it is intended to measure, reliability refers to
how consistent the results are. There are four ways to assess reliability: 3
Internal consistency: Internal consistency examines the consistency of different items within the
same test.
Inter-rater: In this method, multiple independent judges score the test on its reliability.
Parallel or alternate forms: This approach uses different forms of the same test and compares
the results.
Test-retest: This measures the reliability of results by administering the same test at different
points in time.
It's important to remember that a test can be reliable without being valid. Consistent results do not
always indicate that a test is measuring what researchers designed it to.
REFERENCES
1. Newton PE, Shaw SD. Standards for talking and thinking about validity. Psychol Methods.
2013;18(3):301-19. doi:10.1037/a0032969
2. Cizek GJ. Defining and distinguishing validity: Interpretations of score meaning and justifications
of test use. Psychol Methods. 2012;17(1):31-43. doi:10.1037/a0026975
3. Committee on Psychological Testing, Including Validity Testing, for Social Security Administration
Disability Determinations; Board on the Health of Select Populations; Institute of
Medicine. Psychological Testing in the Service of Disability Determination. Washington, DC;
2015.
4. Lin WL., Yao G. Criterion validity. In: Michalos AC, ed. Encyclopedia of Quality of Life and Well-
Being Research. Springer, Dordrecht; 2014. doi:10.1007/978-94-007-0753-5_618
5. Lin WL., Yao G. Concurrent validity. In: Michalos AC, ed. Encyclopedia of Quality of Life and Well-
Being Research. Springer, Dordrecht; 2014. doi:10.1007/978-94-007-0753-5_516
6. Lin WL., Yao G. Predictive validity. In: Michalos AC, eds. Encyclopedia of Quality of Life and Well-
Being Research. Springer, Dordrecht; 2014. doi:10.1007/978-94-007-0753-5_2241
7. Ginty AT. Construct validity. In: Gellman MD, Turner JR, eds. Encyclopedia of Behavioral
Medicine. Springer, New York, NY; 2013. doi:10.1007/978-1-4419-1005-9_861
8. Johnson E. Face validity. In: Volkmar FR, ed. Encyclopedia of Autism Spectrum Disorders.
Springer, New York, NY; 2013. doi:10.1007/978-1-4419-1698-3_308
9. Almanasreh E, Moles R, Chen TF. Evaluation of methods used for estimating content validity. Res
Social Adm Pharm. 2019;15(2):214-221. doi:10.1016/j.sapharm.2018.03.066
