UNIT-II
Lecture-1
Software project estimation
Effective software project estimation is important activity in software development
project.
Estimation is software engineering is a procedure that predicts the time and budget
that required for completing a project.
Project estimation requires the use of complex tools & good mathematical as well as
knowledge about planning.
One of the main reasons software programs fail in our inability to accurately estimate
software size.
Responsible person:
Software Manager
Cognizant Engineers
Software Estimators
User Schedule
Requirements
Constraints So ware Project Efforts
Es ma on
Organiza onal Cost
Policies
Factors effect on Project Estimation
1. Cost: The project will fail if you do not have sufficient funds to complete it. So, At early
stage estimate project cost & ensure you have enough money to complete the work.
2. Time: Estimate both overall project duration & timing of individual tasks. It also enables
you to manage client expectations for key deliverables.
3. Size & Scope: All the tasks that must be completed in order to deliver product on time.
You can ensure that you have right materials & expertise on the project by estimating how
much work is involved and exactly what tasks must be completed.
4. Risk: Estimating predicting risk, what events will occur during the project's life cycle and
how serious they will be. Create risk management plans.
5. Resource's: Resource management ensures that you have all the resources you require &
make best use of them. Like, tools, people, materials, hardware, software & other resources
Steps of Software Project Estimation
1. Estimate Project Size
2. Estimate Efforts (Person per month/hr)
3. Estimate Project Schedule (Month/Year)
4. Estimate Project Cost (Currency/Dollars)
Steps of Software Project Estimation
1. Estimate Product Size (LOC & FP):
It is the very first step to make an effective estimation of the project.
A Customer's requirements, SRS Document & System design document used for
estimating the size of a software.
Estimate project size can be through similar project developed in past. This is called
estimation by Analogy.
The system is divided into several subsystems depending on functionality & size of
each subsystem is calculated.
2. Estimate Project Efforts:
The estimation of effort can be made from the organizational specifics of SDLC.
Software development project involves Design, Coding, Testing, Writing, Reviewing
documents, Implementing prototypes & Deliverable it decide overall project efforts.
The project effort estimate requires you to identify and estimate & then sum up all the
activities you must perform to build a product of the estimated size.
There are two main ways:
1. The best way to estimate effort is based on the organization's own historical data of
development process. Suppose you have similar SDLC, Project size, Development
methodology, Tools, Team with similar skills and experience for the new project.
2. If the project is in different nature which requires the organization to adopt different
strategy or different models based on algorithmic approach. Ex. COCOMO Model.
3. Estimate Project Schedule:
It involves estimating number of people who will work on the project & what they
will work on (the Work Breakdown Structure).
Also, when they will start working on project & when they will finish.
Once you have this information, you need to lay it out into a calendar schedule.
Efforts in man-month are translated to calendar months thumb rule is used.
Schedule in calendar months = 3.0 * (man-months)1/3
The parameter 3.0 is variable, used depending on the situation which works best for
the organization.
4. Estimate Project Cost:
The cost of a project is derived not only from the estimates of person efforts and size.
Other parameters such as purchase hardware, software, travel for meeting.
telecommunication costs (long distance phone calls, video-conferences), training,
office space etc.
Exactly how you estimate total project cost will depend on how your organization
allocates costs.
The simplest labour cost can be obtained by multiplying the project's effort estimate
(in hours) by a general labor rate ($ per hour).
A more accurate labor cost would result from using a specific labor rate for each staff
position (e.g., Technical, QA, Project Management, Documentation, Support, etc.)
