Some type of usability testing fits into every phase of a development lifecycle. The type of testing is distinguished by the research questions asked, the state of the completeness of the product, and the time available for implementing solutions to problems revealed in testing. This chapter outlines four types of tests that fit into the general phases that any product development cycle goes though (see Figure 3-1).
The literature is filled with a variety of testing methodologies, each with a slightly different purpose. Often, different terms are used to describe identical testing techniques. Needless to say, this can be extremely confusing. In deciding which tests to discuss and emphasize, the most beneficial approach might be to use the product development lifecycle as a reference point for describing several different types of tests. Associating a test with a particular phase in the lifecycle should help you understand the test's purpose and benefits.
We discuss three tests — exploratory (or formative), assessment (or summative), and validation (or verification) tests — at a high level, according to the approximate point in the product development lifecycle at which each would be administered. The fourth type of test, the comparison test, can be used as an integral part of any of the other three tests and is not associated with any specific lifecycle phase.
The basic methodology for conducting each test is roughly the ...