Practical example

In the real-world examples below the testability review was carried out as an activity of evaluation:

• A supplier of packages has achieved a return-on-investment of 10:1 through early testing of the designs. Because of this, €21.4 million is saved annually on project costs, and the average time-to-market has been reduced by 1.8 months.
• A company in the telecommunications sector avoids 33 hours of reworking per defect by evaluating the code.
• A large computer manufacturer saves 20 hours of test effort and 82 hours of reworking for every hour spent on inspections.
• A multinational in the chemical sector spends 10 times less maintenance money on 400 inspected software products than on 400 non-inspected software products.

Example of positive influence of adjusting the plan

A government organisation decided to have the designers supplement the functional design with decision tables. The idea behind this was that the designers themselves knew the intention of the design better than the testers, who had to create the (logical) test cases based on the design. Since the testers were thus given a ‘head start’ and needed to investigate less, the organisation reduced the amount of time by 25% in the Specification phase.

Synergy between evaluation and development / testing process

In some organisations, design specifications are structurally evaluated before a subsequent development phase is started. By making the various points of focus from the Preparation phase part of such an evaluation, a satisfactory degree of synergy is created between the structural evaluation and the test activities from the Preparation phase. In this situation, one or more members of the test team participate in the evaluation process. They take responsibility for the aspect of testability in relation to the design specifi cations. The testers can also take the initiative of introducing a structural evaluation process (requirements being, for example, set out in a SMART1 framework), using evaluation techniques as described in Evaluation Techniques. Evaluation then becomes an integral part of the test approach. In the execution of the evaluation activities, use can of course be made of the various checklists as described in the task Create Checklists (AST)).