9.5 TIPS
for clearer data

Every visualization is the answer to a question. Without a clear message, you pick a chart type at random — and your audience feels the confusion.

PITFALL — opening Excel or Power BI and picking a chart type before you know what you want to say.

Look at your data before you look at the shape. Identical averages can hide completely different patterns (see Anscombe’s quartet). A good chart follows principles, not taste.

PITFALL — trusting the average and the trend line without ever looking at the individual points.

A bar chart that doesn’t start at zero exaggerates every difference. A 5% gap can suddenly look like 29%.

PITFALL — letting the axis auto-"zoom in" because the difference looks more dramatic that way.

Pie charts only work with a handful of slices that add up to 100%, sorted from largest to smallest, with direct labels. Often another shape suits your message better.

PITFALL — a pie chart with ten slices, a 3D effect, and percentages that don’t add up to 100%.

Combining two lines on two different axes looks insightful, but quickly distorts the real proportions.

PITFALL — putting two series on two axes side by side without checking whether the scale ratio is fair.

Show what the reader actually wants to know — the gap between target and result — instead of two separate lines they have to subtract themselves.

PITFALL — showing target and result as two separate lines and making the reader do the subtraction.

Color is functional: sequential, categorical, diverging, or a warning. Use it deliberately, and account for color blindness.

PITFALL — giving every category its own color "because you can," without accounting for color blindness.

The title of your chart steers what people see. "Revenue by region" is an axis label, not a message.

PITFALL — using the axis label as the title instead of the conclusion.

Every element that adds no information costs attention that should have gone to the data.

PITFALL — adding shadows, 3D, and gridlines to make it look "finished."

The best visualizations aren’t made in one pass. Perfection is reached when nothing more can be removed, not when nothing more can be added.

PITFALL — sending the first version that works, without sleeping on it first.