The total test points calculated above can be used to derive the total testing time in hours for performing testing activities. This testing time is called primary test hours (PTH), as it is an estimate for primary testing activities such as preparation, specification, and execution. This is calculated as

$ P T H=T T P \times \text { productivity factor } \times \text { environmental factor } $

Productivity factor: It is an indication of the number of test hours for one test point. It is measured with factors such as experience, knowledge, and skill set of the testing team. Its value ranges between 0.7 to 2.0. However, explicit weightage for testing team experience, knowledge, and skills have not been considered in this metric.

Environmental factor: Primary test hours also depend on many environmental factors of the project Depending on these factors, it is calculated as

$\text{Environmental factor} = \text{weights of (test tools+development testing+}$ $\text{test basis+development environment+testing environment+testware)/21}$

These factors and their weights are discussed below.

Test tools: It indicates the use of automated test tools in the system. Its rating is given in below table,

$\begin{array}{|c|c|}\hline 1 & {\text { Highly automated test tools are used }} \\ \hline 2 & {\text { Normal automated test tools are used }} \\ \hline 4 & {\text { No test tools are used }} \\ \hline \end{array}$

Development testing: It indicates the earlier efforts made on development testing before system testing or acceptance testing for which the estimate is being done. If development test has been done thoroughly, then there will be less effort and time needed for system and acceptance testing, otherwise it will increase. Its rating is given in below table

$\begin{array}{|c|c|}\hline 2 & {\text { Development test plan is avalable and test team is aware about the test cases and their results }} \\ \hline 4 & {\text { Development test plan is available }} \\ \hline 8 & {\text { No development test plan is available }} \\ \hline\end{array}$

Test basis: It indicates the quality of test documentation being used in the system. Its rating is given in below table

$\begin{array}{|c|c|}\hline 3 & {\text { Verification as well as validation documentation are available }} \\ \hline 6 & {\text { Validation documentation is available }} \\ \hline 12 & {\text { Documentation is not developed according to standards }} \\ \hline \end{array}$

Development environment: It indicates the development platforms, such as operating systems and languages for the system. Its rating is given in below table,

$\begin{array}{|c|c|}\hline 2 & {\text { Development using recent plattorm }} \\ \hline 4 & {\text { Development using recent and old plattorm}} \\ \hline 8 & {\text {Development using old plattorm }} \\ \hline \end{array}$

Test environment: It indicates whether the test platform is a new one or has been used many times on the systems. Its rating is given in below table,

$\begin{array}{|c|c|}\hline 1 & {\text { Test platform has been used many times }} \\ \hline 2 & {\text { Test platform is new but similar to others already in use }} \\ \hline 4 & {\text { Test platform is new }} \\ \hline \end{array}$

Testware: It indicates how much testware is available in the system. Its rating is given in below table.

$\begin{array}{|c|c|}\hline 1 & {\text { Testware is available along with detailed test cases }} \\ \hline 2 & {\text { Testware is available without test cases }} \\ \hline 4 & {\text { No testware is available}} \\ \hline \end{array}$