Metrics are the most important responsibility of the QA team.Metrics allow for deeper understanding of the performance of the application and it's behaviour. The fine tuning of the application can be enhanced only with the metrics.In a typical QA process,there are many many merics which provides information.

1.Functional or Test Coverage Metric
It can be used to measure the test coverage prior to software delivery.It provides a measure of the percentage of the software tested at any point during testing.
It is calculated as follows:
Function Test Coverage=FE/FT
FE is the number of test requirements that are covered by test cases that were executed against the software
FT is the total number of test requirements

2.Software Release Metrics
The software is ready for release when:
1.It has been tested with a test suite that provides 100% functional coverage,80% branch coverage and 100% procedure coverage.
2.There are no level 1 or 2 severity defects.
3.The defect finding rate is less than 40 new defects per 1000 hours of testing .
4.The software reaches 1000 hours of operation.

3.Software Maturaity Metric
This metric is used to determine the readiness for the release of software system.This index is especially useful for assessing release readiness whwn changes, additions, or deletions are made to existing software systems.It is caluculated as:
SMI=Mt-(Fa+Fc+Fd)/Mt where
SMI=Software Maturity Index Value
Mt=Number of software functions in current release
Fc=Number of functions that contains changes from the previous release
Fa=Number of functions that contains additions to the previous release
Fd=Number of functions that are deleted from the previous release