How to choose the right chart: match the chart to the message on your slide

Start from the sentence you want the slide title to say, then pick the chart that shows exactly that sentence. Gene Zelazny's book Say It with Charts sorts the choice into five relationships: component (parts of a whole), item (ranking and comparison), time series, frequency distribution and correlation. The table below maps them to the chart types you will actually use.

The reason bars come first is perception, not taste. In a 1984 paper in the Journal of the American Statistical Association, William Cleveland and Robert McGill found that people judge position along a common scale more accurately than angle or area. A bar chart relies on position and length. A pie chart relies on angle. Microsoft's page on available chart types in Office lists the full set, including histogram, scatter, treemap, funnel and waterfall charts, and says what each is for.

Use columns or bars to compare categories and a line for change over time, as Microsoft's chart-types page does: bar charts compare individual items and line charts show continuous data over time on an evenly scaled axis. Three habits make the difference between a chart that reads at a glance and one that needs a caption:

• Sort by value unless the categories have a natural order such as months or age bands.
• Start the value axis at zero for bars and columns, because the length of the bar is the value.
• Highlight one bar in the accent color and leave the others gray, so the eye lands on the message.

Choose bars over columns when the labels are long, because horizontal text is easier to read than rotated text. Then write the title. A label such as "Revenue by region" describes the chart. A finding tells the reader what to see in it. The guide to action titles goes into the method.

Use a line chart, with as few lines as the message needs. A line shows direction, speed and turning points better than any other type. When there are several series, label the lines directly at their ends instead of sending the reader to a legend, and highlight the one that matters.

Microsoft also says on the same page that it prefers a line chart over a non-stacked area chart, because one series can hide another. A single series is the exception: an area under one line makes growth feel solid, which is why the example below uses it for annual recurring revenue (ARR). For a handful of periods, columns are fine too, and they make it easier to read each period's value.

Rarely, and only under the conditions Microsoft gives: one data series, no negative values, almost no zero values and no more than seven categories. Microsoft also says doughnut charts are not easy to read, so skip them. A pie chart earns its place when you show two to four parts of one whole and the message is roughly how big one part is, such as "about half of revenue comes from one customer".

As soon as the reader has to compare slices, switch to a sorted bar chart. Cleveland and McGill's finding explains why: comparing angles is harder than comparing lengths. Direct labels with values help a pie chart, but they are a sign that a table or a bar chart would have been clearer.

Use a waterfall chart, also called a bridge chart. It starts at one total, adds each increase and decrease as a floating bar and ends at the new total, which makes it the standard chart for profit bridges and budget variances. Microsoft describes it as showing a running total as values are added or subtracted. The glossary entry on the waterfall chart covers how to read one.

Whichever tool draws it, the input is the same: the start total, each increase and decrease, and the end total. Check that the steps add up to the end value. Color increases, decreases and totals differently or label the bars directly, and make the title name the biggest driver. The board example below does exactly that.

Most bad charts fail in the same few ways, and nearly all of them come from decoration or from a scale that exaggerates. The glossary entry on the data-ink ratio explains the principle: every mark on the chart should carry information.

Also check what the chart leaves out. If a value is missing for a period, show the gap or say so in a note. A missing value silently drawn as zero is a false statement.

When readers need exact values, when you have only a handful of data points or when the numbers have different units. A chart shows a pattern. A table lets someone look up a figure. If your slide has to carry both, put the chart on the slide and the table in the appendix, or highlight the one row that matters in the table itself. The guide to presentation rules explains why one message per slide keeps this simple.

Set the theme first, then insert the charts. Microsoft's page on charts and graphs in presentations describes the path: choose Insert → Chart, replace the placeholder data in the worksheet, then use Chart Elements, Chart Styles and Chart Filters next to the chart to adjust it. For a lot of data or data that changes regularly, Microsoft suggests creating the chart in Excel and pasting it into the presentation.

Chart styles use the theme colors, so changing the theme recolors every chart, as Microsoft explains in its page on changing the color or style of a chart. To recolor a single chart, select it and choose Chart Styles → Color.

Ask the AI for a chart, or mark an area and click "As chart". You can move, resize, duplicate or delete a chart by hand, and when the numbers change, you edit them in the editor or ask the AI for an update. The quality of the result depends on what you provide: the chart type, the values, the units, the periods and the source. A missing value should not silently become zero, so say what is missing.

Tables export to PowerPoint as tables with editable cells, so a table is easy to keep next to a chart when readers need exact values.

Treat the result as a first version and check every number against your source before the slide leaves your hands. The page on an AI PowerPoint generator explains the wider workflow, from the plan of pages to the export.