Rectilinear coordinate graphs are so familiar that it is easy to lose sight of the radical abstraction required to represent diverse quantities, such as pitch, as distances along an axis. Musical notation, which charts pitch as a function of time, also has an ancient origin and illustrates the spatial display of essentially nonspatial information. The first diagrams to communicate quantitative information-about location and distance-were maps: Egyptian cartographers employed coordinate systems in maps prepared 5,000 years ago, and cartography remains a relatively well developed area of graphical representation. Informal observation also suggests that sociologists usually analyze numerical data without the assistance of statistical graphs, a situation that may be changing.īroadly construed, graphic communication dates to the cave paintings of human prehistory and to the earliest forms of writing, which were pictorial or semipictorial. Nevertheless, even a cursory examination of publications in the field reveals that sociologists much more frequently report numerical information in tabular than in graphical form. Sociology, of course, is not a wholly quantitative discipline. Figure 1, from Cleveland (1984), shows the relative space devoted to graphs in leading scientific publications, including four sociology journals. This article emphasizes the role of graphs in data analysis, although many of the considerations raised here also apply to graphical presentation.Īlthough it generally is recognized that the pictorial representation of information is a particularlyĮffective mode of communication, statistical graphs seldom appear in sociological publications. Computational graphs are convenient when statistical tables would be unwieldy, but computer programs are even more convenient, and so nomographs are used with decreasing frequency. Computational graphs ("nomographs") sometimes display data but usually show theoretical quantities such as power curves for determining sample size. Data analysis employs these graphical forms as well as others. Presentation graphs include the familiar bar graph, pie chart, line graph, scatterplot, and statistical map. Statistical graphs present data and the results of statistical analysis, assist in the analysis of data, and occasionally are used to facilitate statistical computation.
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