An economical method of presenting a summary of complex information is to cast it in tabular or graphic form. Narrative descriptions of data necessarily arrange ideas in linear order, one idea after another in single file. In contrast, tables and graphs are able to display a quantity of information concurrently, enabling readers not only to view a variety of items simultaneously but also to grasp the items' interrelationships.

Tabular Summaries

Tables consist of lists of items arranged in rows and columns. The simplest type is a list of items, such as (a) nations listed by population size, (b) students listed by grade point average, (c) occupations ranked by average income, (d) neuroses listed by number of cases, or (e) automobile models ranked by popularity. Another common kind of table shows the interaction of two variables by arranging one variable along the vertical axis and the other along the horizontal axis. Then, within the body of the table, data are entered to show how the variables interact. Several dimensions can be accommodated in a matrix if, along both axes, subcategories of variables are included. By such a device, Table 11-2 accommodates four variables on the horizontal and vertical axes (grade level and sex on the x axis, district and school on the y axis) plus a fifth variable within the cells (average mathematics test scores). As the table suggests, using the rows to represent the more extensive series of variables (districts and schools) makes more efficient use of page arrangement in a research report than does assigning those variables to the columns.

A narrative accompanying Table 11-2 can direct readers' attention to significant features of the data. For example, girls tended to score slightly higher than boys at the third-grade level in Districts 3 and 8. However, at the sixth-grade level in all three districts, boys scored slightly higher than girls. In addition, the lowest (Bayside) and the highest (Carlton and Elm Grove) scores occurred in the same district (District 8) at both the third-grade and sixth-grade levels.

Graphic Summaries

Graphs are diagrams that communicate multiple variables and their interrelationships in a way that would be difficult to convey in a narrative. Whereas tables are generally superior to graphs in summarizing multiple precise quantities, graphs are usually more effective for showing complex interactions among variables. The types of graphic displays illustrated in the following section are pie charts, trend graphs, time lines, histograms, path analyses, theory structure charts, maps, flow charts, and organization charts.