Truncated axes that exaggerate change, dual axes that imply correlation, pie charts with too many slices, a rate shown as a raw count. Pick the chart for the question: trend to a line, comparison to a bar, part-to-whole to a stacked bar. Label units, start counts at zero, and drop the decoration — the goal is an honest, fast read.
How to answer it
A chart misleads when the visual size of something does not match the size of the thing it represents, or when it implies a relationship the data does not support.
The usual offenders:
A truncated y-axis on a bar chart. Bars encode length, so a 3% difference drawn on an axis that starts at 95 looks like a 60% difference. Start bars at zero; if a small change needs to be visible, use a line chart or plot the change itself.
Dual axes. Two lines on different scales can be made to cross anywhere, so they suggest correlation that is an artefact of the scaling. Use two panels.
Pie charts with many slices or similar values. People cannot compare angles; a sorted bar chart does the same job readably.
Raw counts where a rate is the question. More incidents in a bigger city is not more risk. Normalise.
Cumulative charts to hide a slowdown. A cumulative total only ever goes up.
Cherry-picked windows. A trend that starts at the one low point.
The positive rule: choose the chart by the question. Trend over time, a line. Comparison across categories, a sorted bar. Part of a whole, a stacked bar or a single number. Relationship between two variables, a scatter. Then label units, state the time window, and remove everything that is not data.
What they are checking: the axis and dual-axis cases, and a rule for choosing chart types.
Common mistake: defending the truncated axis as "showing the detail". It shows a detail at the size of a headline.