How to calculate Error Discovery Rate ?

Error Discovery Rate is the ratio of Total no. of defects found in application to Total no. of test cases or scripts executed.

Error Discovery Rate metric is used to determine the effectiveness of the test cases and measured at test execution phase.

How to calculate Error Discovery Rate:

Error Discovery Rate = Total no. of defects found in application /Total no. of test cases or scripts executed

Example:

Total no. of defects found in application	Total no. of test cases or scripts executed	Error Discovery Rate
250	1000	0.25

Error Discovery Rate = 250 /1000

                                      = 0.25 Defects/ Test Cases