HANDLING ATTENTION POINTS◆ 177
1994
Personal digital assistants (PDAs)
Personal computers
Mobile phones
Number of appliances bought (thousands)
500
450
400
350
300
250
200
150
100
50
0
1998 2002
(e) Grouped bar chart
Changing patterns of electronics appliances
purchases, UK 1994 to 2002 (hypothetical)
Use a grouped bar chart whenever:
- you want to show how the levels of several indices
vary across a number of different cases or areas or time
periods.
Don’t use grouped bar charts if:
- the data are really shares of something (normally
better to use a percentage component chart).
Points to watch:
- put the bars for each unit into an order that gives the
clearest pattern across the cases (ideally a numerical
progression within each case); - use clearly distinct shadings and provide labels for
each bar.