ABSTRACT
The concept of internal validity is related to the task of reaching unambiguous (valid) conclusions about the relationships among design variables. Imagine that before starting a research project you think ahead for a moment and ask yourself, “What is it that I would like to be able to conclude when I have finished gathering and analyzing my data?” Given that the objective of research is to record and evaluate observations bearing on the relationships among variables, the researcher faces two primary considerations in planning a study. The first, the one covered in the present chapter, is the issue of whether or not the relationship observed is accurately or validly identified or interpreted (internal validity). The second, to be discussed in Chapter Six (external validity), concerns the matter of generalizing from a relationship observed in one set of data to other potential data sets that might have been observed but were not. Questions of internal and external validity need to be considered conjointly when evaluating the overall merit of a given study.
