Tools for Information Literacy

What kinds of charts should we use?

Types of charts

Spreadsheet data can be converted into many different ways of displaying data in charts.
But one needs to know what type of display is best suited for the underlying data.

Charts are a useful way to illustrate data shown in worksheets. Excel has several different types of charts to select from depending on the sort of information you are using and the effect you wish to convey in the graphic.

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to show comparisons

Column charts compare values across categories.

The same is true in Excel for Mac

bar charts are essentially the same thing, but oriented on the horizontal axis. Excel asserts they are the best chart type for comparing multiple values.

The same is true in Excel for Mac

Another way to consider charting parts to a whole

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to show trends or change over a period of time

Line charts compare continuous data over time against a common scale and are ideal for showing trends.

The same is true in Excel for Mac

Area charts are a variant of line charts

Area charts emphasize differences between several sets of data over a period of time.

Scatter charts

Scatter charts compare pairs of values, depicting them as sets of X and Y coordinates.

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percentages

Pie charts display percentages

But column charts do the same and in a more revealing fashion. Use a pie chart to show the relationship or proportion or parts to a whole, only when you want your chart to be metaphoric.

To quote Edward Tufte in The Visual Display of Quantitative Information, p. 178

... the only worse design than a pie chart is several of them ...
Given their low data-density and failure to order numbers along a visual dimension,
pie charts should never be used.

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