`would have to provide a series of different charts for each`

column of numbers being covered.

- You want to both present some primary data numbers, and

then show calculations of how index numbers or ratios or

compound statistics are derived from them. - Tables are being used to put reference material onto the

record, for instance in Annexes or Appendices.

### Designing charts and graphs

We live in a graphical age. In general if it is possible to display

data in chart form rather than in tables it is desirable to do so,

subject only to the exceptions enumerated just above. Charts

and graphs automatically screen out too much data being

thrown at readers. They are easier for you to analyse correctly

as an author, and for readers to interpret. Charts are especially

important in showing the relative importance of different com-

ponents or phenomena; giving trends over time and rates of

growth; and illustrating more complex patterns in data than

just linear relationships, such as ‘curvey’ relationships. There

are now many different types of chart for displaying simple

data available on spreadsheet packages (like Excel or Lotus) and

widely used data-analysis programmes (like SPSSorStata). Both

PhD students and established academics often make mistakes

about choosing the right kind of graphic to go with their data.

Figure 7.1 shows eight of the most commonly used charts and

for each of them points out a few uses for which they are well

or poorly adapted.

As with tables it can be useful to briefly compare a poorly

designed and a well-designed chart version of the same data

tables discussed in the previous section. Figure 7.2 (on p. 182)

is a vertical bar chart version of the table in Table 7.1; and

Figure 7.3 (on p. 183) is a horizontal bar chart version of the

table in Table 7.2. The differences in the accessibility of the two

bar charts are every bit as noticeable as in the readability of the

two tables, and again it is worth briefly itemizing why.

Labelling. Figure 7.2 has a very poor heading and axis labels

compared with Figure 7.3. The choice of a vertical bar design

for Figure 7.2 means that there is no space for the health board

172 ◆AUTHORING A PHD