4.5: Acceptance Tests

• For large implementation projects, the customer or manager usually sets objective and measurable goals for hardware and software performance.
• If the completed product fails to meet these acceptance criteria, the system must be reworked until success is demonstrated.
• Rather than the vague and misleading criterion of "user friendly," measurable criteria for the user interface can be established for the following:
• Time to learn specific functions
• Speed of task performance
• Rate of errors by users
• Human retention of commands over time
• Subjective user satisfaction
• In a large system, there may be eight or 10 such tests to carry out on different components of the interface and with different user communities.
• Once acceptance testing has been successful, there may be a period of field testing before national or international distribution..
• The goal of early expert reviews, usability testing, surveys, acceptance testing, and field testing is to force as much of the evolutionary development as possible into the prerelease phase, when change is relatively easy and inexpensive to accomplish.