The methodology of man-machine systems: Problems of verification and validation

This paper provides an elementary discussion of the problems of verification and validation in the context of the empirical evaluation of designs for man-machine systems. After a definition of the basic terms, a breakdown of the major parts of the process of evaluation is given, with the purpose of indicating where problems may occur. This is followed by a discussion of verification and validation, as two distinct concepts. Finally, some of the practical problems of ascertaining validity are discussed. The general conclusion is that rather than rely blindly on a well-established procedure or rule, one should pay attention to the meaningfulness of the aspects which are selected for observation, and the degree of systematism of the methods of observation and analysis. A qualitative approach is thus seen as complementary to a quantitative approach, rather than antithetical to it.