Choosing the Right Chart

Match the chart to the question

Every chart answers a question. Pick the chart whose shape naturally expresses your question, and your message becomes obvious. Pick the wrong one and readers struggle — or worse, are misled.

The core chart types

• Bar chart — comparison across categories. Which region sells most?
• Line chart — trend over a continuous axis, usually time. How did sales change this year?
• Scatter plot — relationship between two continuous variables. Does price correlate with size?
• Histogram — distribution of a single variable. How are customer ages spread?
• Pie chart — part-to-whole for a few categories. Use with caution.

Line for trends over time, scatter for correlation between two measures, bar for comparing categories, histogram for showing distribution. Memorize these four and you'll rarely go wrong.

Scatter vs line

Use a scatter plot when both axes are independent measurements and you're hunting for a relationship. Use a line chart when the x-axis is ordered (especially time) and you want to show progression. Drawing a line between random points implies an order that may not exist.

Why pie charts get criticized

Humans judge lengths well but angles poorly. A pie with more than a few slices makes comparisons difficult — adjacent slices of similar size are nearly impossible to rank by eye. Bar charts compare the same data more accurately.

Histograms

A histogram bins values into ranges and shows how many fall into each bin — revealing the shape of a distribution: symmetric, skewed, bimodal. It looks like a bar chart but the bars touch, because the x-axis is continuous, not categorical.