How to calculate Test Effectiveness ?

Test Effectiveness is the ratio of difference of Total no. of application defects found by test team and Total no. of application defects rejected by the customer/developer to sum of Total no. of application defects found by test team and Total no. of defects found by customer/test team during UAT.
Test Effectiveness  metric is used to measure the test effectiveness of test team and is calculated at the end of test execution phase.

How to calculate Test Effectiveness:

Test Effectiveness = (Total no. of application defects found by test team - Total no. of application defects rejected by the customer/developer) / (Total no. of application defects found by test team + Total no. of defects found by customer/test team during UAT) *100

Example:

Total no. of defects found by test team	Total no. of defects Rejected by Customer/Dev team	Total no. of defects found by customer/test team during UAT	Test Effectiveness
80	5	2	91.46

   Test Effectiveness = (80-5) / (80+2) * 100

                                 = 91.46 %