Dynamic displays

When information is displayed using a computer (e.g. on a web site), it is possible to show changes over time in a dynamic way. A simple graphical display of the information at one time point can be animated (e.g. using a slider) to show changes over time.

The idea of dynamic displays is most easily explained in an example.

Deaths and injuries on New Zealand roads

The pie chart below initially shows the number of road users of various types who were reported as being killed or injured on New Zealand roads in 1955.

Drag the slider under the pie chart to dynamically show how the numbers changed since 1955.

Clicking the checkbox Only show percentages keeps the pie chart area constant (and therefore does not show changes to the total number of deaths and injuries) and concentrates attention on the types of road user. Observe that:

Select Bar chart from the pop-up menu to show the same information in a dynamic bar chart.

Static display of the same information

When the data display at each time point is simple, it is often possible to avoid a dynamic display and show all the information at once. Select Time series from the pop-up menu. This time series display effectively shows a stacked bar chart at each time point.

The static time series graph of the counts or proportions is more effective than a dynamic display.

Always consider whether the information can be represented in a static display — it is often better than a dynamic graph.