For example : A typical test cycle:
Before Automation -- (AS IS statistics - documented)
Number of Manual test cases = 300
Time taken to execute these test cases = 10 Person days
Tester's productivity = 30 Test cases per day (derived data)
After Automation -- (Assume 150 of these test cases are automated)
How do you think test cycle would look like?
Number of test cases Automated = 150
Number of test cases requiring manual effort = 150
Time taken for 300 test cases = Time for Automated execution + Time for Manual test execution
= (how much time will 150 automated test cases will take to complete) + 5 days (with 30 test cases per day productivity)
= 1 + 5 (assuming that automated tests run at 1/5th of time of manual execution)
= 6 days
Hence a business case will be developed to justify automation investment
The business case would say - with automation, we can save 4 person days of testing effort per cycle. Depending upon how many cycles of testing are lined up - we can break even the automation investment.
Oh... What a great feeling ... This is what I see all day in and out..
Let me tell you one thing .. executives, managers love this stuff ... so neat - objectively stated in numbers, justifying in terms of monetary terms why we need automation.
But some discomfort and terrible feeling in me ... what you people think - we are missing here?