The author needs to decide who the audience is and what they will expect or extract from the graph. When these decisions are made, the question of format and design can be answered. Table 1 illustrates this process. For example, if the author has a time series data set and wants to communicate variation over a period of years, he or she can choose a line chart or, for a short time series, a bar chart. Thus, the fundamental task in designing a statistical graph is to focus readers' attention on the graph's data and its message, not on its design.
Good design supports the data rather than the data supporting the design.
A well-designed graph displays the minimum design and maximum data. For this reason, the emphasis throughout the Guidelines is on choosing the most appropriate format or design to display the features of interest, the message, in a data set. This often can be done, as Table 1 illustrates, in more than one way. EIA products present complex data and complex messages, and the approaches to resolving format and design problems for EIA data need to be flexible. Therefore, the examples presented are not inflexible specifications but, rather, guides to methods to present data clearly and accurately.