In William J. Gilmore’s Reading Becomes a Necessity of Life, tables and graphs are used to make sense of quantified data in a way that is intended to supplement Gilmore’s claims concerning the reading habits of rural American families from 1787 to 1830. One table in particular, Table 8-2, stood out to me because of a few characteristics: it is simple, easy to understand, and self-contained.
As Jane Miller wrote, effective tables are self-contained and well-labeled “so your audience can understand the information without reference to the text” , and I believe this is exactly what Gilmore accomplishes. The table’s header is compact without being too brief and includes a geographic location and time period. The columns are titled with a description and units (when applicable) and are not overly-crowded by lines or extraneous data. He includes a line for a total count at the bottom, which is a helpful feature so that readers can get a feeling for how many libraries are being accounted for. In his explanation, Gilmore groups different parts of the table together in order to make his point. For example, he writes “It is very surprising…that more than a tenth (11 percent) of all libraries contained more than twenty-five volumes…” It was easy for me, as a reader, to look at the table and notice that most of the libraries had only 1-5 books; however, Gilmore’s analysis drove my attention to what is apparently a more surprising observation. In this way, the table is easy to understand, but it is Gilmore’s written analysis that provides the bulk of information about what readers should be paying attention to.
If Gilmore were to demonstrate this data in a graph rather than in a table, I find that there are two possible ways he could go about doing it. The choice of what type of graph to use, of course, depends upon the purpose of what the information will convey. Being as the data is not representative of a trend over time, a line graph is out of the question. A bar or pie chart would be a better method. For example, a bar chart might be used to show how many libraries have a certain number of books (i.e. 90 libraries have only 1 book), with the y-axis measuring the number of libraries and the x-axis divided into increments of 1 volume, 2-3 volumes, 4-5 volumes, and so forth. This, however, would eliminate the “Percent of All Libraries” information that the table provides which Gilmore uses in his analysis. It is possible to label each of the “bars” of the graph according to the percentage that they represent, as long as it doesn’t overcrowd the graph and confuse the data. This, however, might not be as helpful as a pie chart, which could create a visual of, for example, the 90 libraries that have 1 book compared to what all of the other 306 libraries have.
In this particular case, I am convinced of the effectiveness of Gilmore’s original table to the point where I probably would not change to a graphical representation at all. His table is clean and easy to understand; if after experimentation with a bar or pie graph this same simple display of data is not achieved, I would be inclined to keep the table instead.
 Miller 1840 (ebook edition)