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