How to estimate test automation activities?

Sometimes test automation specialists, especially those who takes leading roles on the projects, have to perform the one interesting task, which has not too much in common with technical world. It is called

Estimations

I love to make estimations, do you? Especially, when you know exactly how the things will going on, what kind of application are you going to automate, what is the real performance of your colleagues, and what potential risks you have.

And when you have all of this information? Well, you know... :)

Anyway, how to estimate test automation activities?

I do it in the following way (step by step guide):

1. Create excel spreadsheet.
2. Enter actual number of test cases to automate - #tcs.
3. Calculate average number of steps in test case and enter it - StepsInTestCase.
4. Enter the average time for one step automation - HoursForOneStep.
5. StepsInTestCase*HoursForOneStep - HoursForOneTestCaseAutomation
6. Enter hours for one test case debug - usually it is 30-50% of HoursForOneTestCaseAutomation - and it will be HoursForOneTestCaseDebug. E.x. you can use this formula =ROUND(HoursForOneTestCaseAutomation/2,0)
7. #tcs*(HoursForOneTestCaseAutomation+HoursForOneTestCaseDebug) - HoursForAllTestCasesAutomation.
8. CEILING(HoursForAllTestCasesAutomation/8,1) - DaysForAllTestCasesAutomation.
9. Enter number of test automation engineers in the team - TeamSize.
10. CEILING(DaysForAllTestCasesAutomation/TeamSize,1) - DaysForTeam.
11. CEILING(DaysForTeam/20,0.1) - MonthForTeam.

The automatically calculated number MonthForTeam is all that you need.
- Is it simple?
- Yes.
- Does it works?
- Sure!
- Is it accurate?
- Well, you know the better approach? Please, tell me in the comments below!

Another interesting questions is ROI (return of investment in automation) calculation. But it is for another article..