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and test strategy. Even project sizing calculations cannot be said to be entirely based
on objective assessment.
In any case, even after calculating effort by any method, it should be thoroughly
checked by somebody who has experience in effort estimation. Only then can the
accuracy of the effort calculation be certified. No alternatives have been found for
experience when it comes to effort estimation!
..2
Estimation Using Test Point Analysis
Software products and applications are built using well-defined smaller components.
Each component is integrated with other components through interfaces. These
interfaces have the facility of input/output so that the component can communicate
with other components. For TPA, functions with which the software application
has been built are used as the basic point to calculate the effort estimate.
Function point analysis is a sound technique used for estimating effort for soft-
ware development projects. TPA is built on the basis of function point analysis and
is a very good technique for effort estimation for test projects. TPA can be used to
prepare an estimate for a system test or acceptance test. TPA covers only black box
testing and is not meant to estimate effort for white box testing (unit/integration
testing done by developers). Effort estimates for white box testing are taken care of in
the function point analysis itself. TPA is also used to determine the relative impor-
tance of the various functions in comparison to each other and on the basis of the
entire project. This helps in using the available testing time as efficiently as possible.
In essence, TPA is an objective way to determine effort estimation for test projects.
4.2.1
Basic Components of TPA
TPA calculations are based on three characteristics of the project: the size of the
software application to be tested, the test strategy (test coverage, quality standards,
and complexity of components under test), and the level of productivity. While
productivity of resources varies from resource to resource and from organization to
organization, size and test strategy determine the volume of work to be performed.
This volume is expressed in terms of the number of test points. Multiplying this
volume with productivity will determine the number of hours of test activities to
be performed.
4. 2.1.1
Project Size
When any project is to be initiated, project sizing is the first element that is
determined. You will already have project development size information (num-
ber of function points) available from function point analysis that is done by
