It is always easier to use an existing measure than to develop a new one. Be sure to check the literature for measures that have been successfully used in similar research. A careful reading of the "Procedures" and "Measures" sections of articles will give us information that will help us identify and evaluate the operational definitions used in published research studies. The features of a good operational definition vary depending on the study design. We will examine operational definitions for variables measured in observational, survey, and experimental studies.

Why Is This Important?
The meaning of our study rests on how we objectively observe the construct or behavior of interest. Thus, developing a reliable and valid set of procedures for measuring our variables is crucial for the validity of any research study. Good operational definitions require that we first specify our constructs (see Specifying Constructs workshop); developing reliable and valid operations is the last step of specifying constructs when we are designing our own studies.