Use Charts and Diagrams to Explain Ideas

Charts and diagrams are powerful tools for explaining ideas that are hard to describe with words alone. A well-chosen diagram makes data clearer and helps readers understand patterns, comparisons, or processes at a glance.

Common Diagram Types

• Bar chart — compares amounts or groups side by side.
• Pie chart — shows how a whole is divided into parts (percentages).
• Line graph — tracks change over time.
• Venn diagram — compares two or more things showing similarities and differences.
• Flow chart — shows steps in a process or decision-making sequence.
• Timeline — places events in chronological order.

Labeling a Diagram Correctly

• Always give the diagram a clear title.
• Label the axes (x-axis and y-axis) on graphs.
• Add units of measurement (e.g. cm, kg, %).
• Include a key or legend if colors or patterns are used.
• Note the source of the data below the diagram.

Writing About a Diagram

• Start with "As shown in the diagram / chart...".
• Describe the key finding: what stands out most.
• Explain what the data suggests or why it matters.
• Refer to specific values to support your description.