Explaining a chart without inventing trends

Start with the overview

Begin with the overall picture, not the first number you see. State what the chart shows, the time frame, and the most important pattern. The overview gives the reader a frame; details then fill it. Without an overview, a data description becomes a list of numbers.

Read before you write

Check axes, units, and legend before describing anything. A chart labelled in thousands is not the same as one in millions. Note the start and end points and any obvious peaks or troughs. Misreading a label is the most common source of invented trends.

Describe, do not invent

Report what the data show and avoid explaining causes that are not in the chart. If sales rose in 2020, say they rose; do not claim it was because of a campaign unless the data say so. Use cautious language for any interpretation: "may reflect," "is consistent with."

Select key figures

Choose a few significant numbers: the highest, the lowest, the start, the end, and one or two notable changes. Do not report every value. Group data by category or period to keep the description readable. Precision matters more than completeness.

Language for trends

Use clear verbs: rose, fell, remained stable, fluctuated, peaked, plateaued. Pair them with adverbs of degree: slightly, sharply, steadily. Avoid vague words such as "changed a lot." Match the verb to the size of the change shown.

Common mistakes

• Describing every data point.
• Inventing causes not in the data.
• Misreading units or time frames.
• Overusing the same verb.

A worked example

Chart: website visits by device from 2018 to 2023. Overview: mobile visits grew steadily while desktop visits declined, so mobile became the dominant source. Details: mobile rose from 40% to 68%; desktop fell from 55% to 25%; tablet stayed near 7%. No cause is claimed; the description reports only what is visible.

Practice

Find a simple chart in a report or news article. Write an overview in two sentences and a detail paragraph of four to six sentences. Check every number against the chart. Rewrite any sentence that explains a cause not shown in the data.

Comparing two charts

When a task includes two charts, describe each, then compare them. Do not describe them in isolation and leave the comparison implicit. State the most important similarity and difference in the overview. Use the detail paragraphs to support that comparison rather than repeating descriptions.

A second example

Charts: online sales by category in 2019 and 2024. Overview: clothing remained the largest category, but electronics grew fastest and overtook food. Details: clothing stayed near 35%; electronics rose from 15% to 30%; food fell from 25% to 20%. The comparison is clear and every number is visible in the charts.

Practice with feedback

Find a multi-chart task or report. Write an overview of two sentences and a detail paragraph of five sentences. Check that every claim is visible in the data. Ask a peer to identify the main trend from your overview alone.

Common mistakes revisited

• Describing every data point.
• Inventing causes not in the data.
• Misreading units or time frames.
• Overusing the same verb.
• Leaving the comparison implicit.

A quick reference

Start with the overview, check labels, select key figures, and hedge interpretations. This four-step routine keeps descriptions accurate and readable.

Mini-exercise

Describe: "Visits to the site rose from 10,000 in January to 15,000 in June, then stayed near 15,000 for the rest of the year." Answer: "Visits increased steadily in the first half of the year and then plateaued." The description reports the trend without inventing a cause.

Related lessons

Use careful claims with using cautious language in academic writing, separate fact from inference with separating fact, opinion and inference, and set goals with choosing speaking goals you can observe.