There are many effort estimation techniques, but in this post we will focus on few of them and will understand the basic concepts of them.before explaining Software Testing Estimation Techniques, first we start with some basic questions…
What is Testing Estimation? why we need it? who should do it?
Estimation is the process of finding an estimate, or approximation, Estimation is a some value, Effort estimation in software testing is process the finding an estimate or time to complete certain testing activity. lets say, to complete test execution QA will require 5hrs, so here 5 hours is estimation. now from where is 5 hours come/ derived? to find such estimation we need Estimation technique.
Why we need it? : to Achieve certain goal. and who should do it? off course, Test Manager, Test Lead. in small companies, Sr. QA can also do it. do the estimation respective person should know the all aspect of software by which QA can do effective testing estimation.
Following are some popular effort estimation techniques which we can used for Software testing estimation:
- Function point Analysis/ Test Point Analysis:
- Work Breakdown Structure (WBS)
- Delphi Technique
- Three-point estimation (successive calculation)
- Use case point estimation method
- FIA- Finger in the Air (Best Guess)
2) Work Breakdown Structure:
It is created by breaking down the test project into small pieces. Modules are divided into sub-modules. Sub modules are further divided into functionality and functionality are divided in sub-functionality.
Review all the requirements from Requirement Document to make sure they are added in WBS. Now you figure out the number of tasks your team needs to complete. Estimate the duration of each task.
3) Delphi Technique :
Here functionality and each task is allocated to each team member. Then team member gives estimate that they will take this much hours to complete the task.
Averagely, this technique gives good confidence in the estimation. This technique can be combined with other techniques.
5) Three Point Estimation () :
This technique is based on statistical methods In this technique, task is broken down into sub-tasks (similar to WBS) and then three types on estimation are done on each chunk –
Optimistic Estimate (Best case scenario in which nothing goes wrong and all conditions are optimal.) = A
Most Likely Estimate (most likely duration and there may be some problem but most of the things will go right.) = M
Pessimistic Estimate (worst case scenario which everything goes wrong.) = B
Formula to find Value for Estimate (E) = A + (4*M) + B / 6
Standard Deviation (SD) = = (B – A)/6
now a days, planning poker and Delphi estimates are most popular testing estimation techniques.