I recently replied on a blog site about this topic and thought of posting.
Measuring effective testing
1. During Requirement Analysis and test case Development
One of the analysis could be, how effective has the test team been when it was about reading the RA. Were question asked across to BA or Product Manager and were there any changes made to the RA, because of the forecasting skills of the tester.
Also how effective the test coverage is with respect to making test cases were, this can be found simply by a good test case review. Has the test case covered all possible scenarios? Or there was some slippage.
2. Execution phase
Probably the best time to make different types of reports/ metrics for measuring “Effective testing”, there could be many to list down. However one of the important ones is the test case coverage with respect to bug reporting. If there was a proper test case making cycle then do all issues reported have test cases linked to them. So basically checking if the testing team was efficient enough during the RA and Test case Development phase.
3. Post release, feedback from the customer.
The most important phase where the effectiveness of testing can be measured is the phase where you could run the Defect Leakage metrics, according to me it could be simplified with respect to # of defects that the Client found compared with # of defects that the test team found. However # of defects would simply mean to calculate a number, the important thing here would be to find out what is the severity of defects that were slipped out by the test team.