Test Metrics

Posted: August 30, 2012 in Testing Basics
Tags: , , ,

Test Metrics:

The objective of Test Metrics is to capture the planned and actual quantities the effort, time and resources required to complete all the phases of Testing of the SW Project. It provides a measure of the percentage of the software tested at any point during testing.
Test metrics should cover basically 3 things:
1. Test coverage
2. Time for one test cycle
3. Convergence of testing

There are various types of test metrics. Different organization used different types of test metrics.

Functional test coverage:It can be calculated as:
FC=Number of test requirements that are covered by test cases/Total number of test requirements.

Schedule Variance:Schedule Variance indicates how much ahead or behind schedule the testing is. It can be calculated as:
SV = (Actual End Date-Planned End Date) / (Planned End Date-Planned Start Date+1)*100

A high value in schedule variance may signify poor estimation. A low value in schedule variance may signify correct estimation, clear and well understood requirements.

Effort Variance: Effort may be measured in person hours or person days or person months. Effort variance would be computed for all tasks completed during a period .It can be calculated as:
EV= (Actual effort-Estimated effort)/ (Estimated Effort) X 100%

A high positive value of effort variance may signify optimistic estimation, changing business processes, high learning curve, new technology and/or functional area.
A high negative value of effort variance may signify pessimistic estimation or excessive buffering an efficient and skilful project team, high level of componentization and re-usability, clear plans and schedules.
A low value of effort variance may signify accuracy in estimation, timely availability of resources, no creeping requirements.

Defect Age (In Time): Defect Age is used to calculate the time from Introduction to Detection.
Average Age = Phase (Detected – Introduced) / Number of Defects

On-Time delivery: This metrics sheds light on the ability to meet customer commitments. On time delivery may be tracked during the course of the project based on the actual delivery dates and planned commitments for the deliveries done during a period.
OTD= ((No. Of Delivery on time)/Total No of due Delivery)*100

A low value of %On time delivery may signify poor planning and tracking, delays on account of customer, , incorrect estimation, or may point to a project risk having occurred.
A large value of %on time delivery may signify good planning, tracking and foresight, with a high responsiveness for immediate corrective action; a receptive customer, high commitment of the team, and good estimation.

Test cost: It is used to find resources consumed in the testing.
TC= test cost Vs total system cost
This meets identifies the amount of resources used in testing process.

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