Because the results of a single-subject study do not involve any traditional statistical methods, researchers must rely on the visual inspection of a graph to convey the meaning of their results.
The graph in Figure 14.1, for example, appears to indicate that a substantial change in behavior occurred when the treatment program was started. However, the graph by itself is not a convincing demonstration that the treatment actually caused a change in behavior. In fact, there are two reasons for skepticism concerning the results.