ABSTRACT
This chapter deals with experimental design in psychology. If case-studies in clinical psychology are designed in a particular way, perhaps by making use of some of the single-case experimental designs mentioned in D. H. Barlow and M. Hersen, experimental control is certainly present. There are a number of standard experimental designs that can be used to control variables and, at the same time, determine whether possible alternative explanations can be ruled out. A subsidiary goal that must be considered is the careful examination of the meaning and the method of measurement of the psychological variables relevant to the experiment. In an experiment investigating speed of information processing, performance may be operationally defined as the reaction times people have to certain stimuli. A useful rule of thumb is to consider many different ways of measuring the psychological construct of interest and determine the extent to which each method could yield different experimental results.
