Data Graphs in Introductory and Upper Level Psychology Textbooks: A Content Analysis

In this article, we report a content analysis of data graphs in introductory and upper level psychology textbooks. Three raters classified data graphs as either line, bar, scatter, 100%, or picture graphs. The results indicated that (a) only 5 types of data graphs appear in psychology textbooks, (b) the number of data graphs per page varies considerably in both types of textbook, and (c) comparisons of observed and expected frequencies revealed that proportions of 100% graphs were greater in introductory textbooks and proportions of scatter graphs were greater in upper level textbooks. We discuss implications of these findings for teachers of psychology and authors of undergraduate psychology textbooks.