Evaluation researchers are interested in the same three levels of effect that were mentioned in Chapter 15’s discussion of copy research: cognitive, affective, and conative. At the cognitive level, researchers attempt to find out how much people learned from the public relations campaign. At the affective level, measures of changes in attitudes, opinions, or perceptions are used frequently. Finally, behavioral change, at the conative level, is an important way to gauge public relations impact. Obviously, the techniques used in advertising campaign effectiveness studies—pretest/posttest and tracking studies—can be applied in measuring the impact dimension of public relations campaigns. Public relations researchers should be aware of some common mistakes that can affect evaluation research. Baskin, Aronoff, and Lattimore (1997) caution against the following: