88 PART 2 Examining Tools and Processes

For a deeper dive into epidemiologic study designs, we encourage you to read

­Epidemiology For Dummies by Amal K. Mitra (Wiley) and pay special attention to

Chapters 16 and 17, which are about causal inference and study design.

Presenting the Study Design Hierarchy

Figure 7-1 illustrates the epidemiologic study designs in terms of their relation-

ship with each other in a hierarchy as they apply to human health research (not

animal research or other domains of human research like psychology). As shown

in Figure 7-1, human health research may be split into two types: observational

and experimental.

Observational research is where humans are studied in terms of their health and

behavior, but they are not assigned to do any particular behavior as part of the

study — they are just observed. For example, imagine that a sample of women

were contacted by phone and asked about their use of birth control pills. In this

case, researchers are observing their behavior with regard to birth control pills.

FIGURE 7-1:

Study design

hierarchy.

© John Wiley & Sons, Inc.