Software Test Estimation - 9 General Tips on How to Estimate Testing Time Accurately

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For success of any project test estimation and proper execution is equally important as the development cycle. Sticking to the estimation is very important to build good reputation with the client.

Experience play major role in estimating "software testing efforts". Working on varied projects helps to prepare an accurate estimation for the testing cycle. Obviously one cannot just blindly put some number of days for any testing task. Test estimation should be realistic and accurate.

In this article I am trying to put some points in a very simple manner, which are helpful to prepare good test estimations. I am not going to discuss the standard methods for test estimations like testing metrics, instead I am putting some tips on - How to estimate testing efforts for any testing task, which I learned from my experience.

Factors Affecting Software Test Estimation, and General Tips to Estimate Accurately:

1) Think of Some Buffer Time
The estimation should include some buffer. But do not add a buffer, which is not realistic. Having a buffer in the estimation enables to cope for any delays that may occur. Having a buffer also helps to ensure maximum test coverage.

2) Consider the Bug Cycle
The test estimation also includes the bug cycle.  The actual test cycle may take more days than estimated. To avoid this, we should consider the fact that test cycle depends on the stability of the build. If the build is not stable, then developers may need more time to fix and obviously the testing cycle gets extended automatically.

3) Availability of All the Resources for Estimated Period
The test estimation should consider all the leaves planned by the team members (typically long leaves) in the next few weeks or next few months. This will ensure that the estimations are realistic. The estimation should consider some fixed number of resources for test cycle. If the number of resources reduces then the estimation should be re-visited and updated accordingly.

4) Can We Do Parallel Testing?
Do you have some previous versions of same product so that you can compare the output? If yes, then this can make your testing task bit easier. You should think the estimation based on your product version.

5) Estimations Can Go Wrong - So re-visit the estimations frequently in initial stages before you commit it.
In early stages, we should frequently re-visit the test estimations and make modification if needed. We should not extend the estimation once we freeze it, unless there are major changes in requirement.

6) Think of Your Past Experience to Make Judgments!
Experiences from past projects play a vital role while preparing the time estimates. We can try to avoid all the difficulties or issues that were faced in past projects. We can analyze how the previous estimates were and how much they helped to deliver product on time.

7) Consider the Scope of Project
Know what is the end objective of the project and list of all final deliverables. Factors to be considered for small and large projects differ a lot. Large project, typically include setting up test bed, generating test data, test scripts etc. Hence the estimations should be based on all these factors. Whereas in small projects, typically the test cycle include test cases writing, execution and regression.

8 ) Are You Going to Perform Load Testing?
If you need to put considerable time on performance testing then estimate accordingly. Estimations for projects, which involve load testing, should be considered differently.

9) Do You Know Your Team?
If you know strengths and weaknesses of individuals working in your team then you can estimate testing tasks more precisely. While estimating one should consider the fact that all resources may not yield same productivity level. Some people can execute faster compared to others. Though this is not a major factor but it adds up to the total delay in deliverables.