Data interpretation mastery: tables, graphs, and charts

By Marin Devereux·7 min read·

Data interpretation is the single most common question type in numerical reasoning tests. You are given a table, bar chart, line graph, or pie chart and asked to calculate, compare, or extrapolate. The data is always sufficient — the challenge is finding it fast.

The reading order that saves time

  1. Read the question first. Know what you need before looking at the data.
  2. Read titles, axis labels, and units. Is it thousands or millions? Quarterly or annual?
  3. Locate the relevant data points. Ignore everything else.
  4. Calculate and sanity-check. Does the answer feel right given the scale?

Regional revenue ($ millions)

Example data — use this to answer the question below.
Try it
Based on the chart above, what percentage of total revenue comes from APAC?

Total = 42 + 38 + 56 + 14 = 150. APAC share = 42 / 150 = 28%.

Trap: candidates often calculate 42 / 56 (comparing to the largest region) instead of 42 / 150 (share of total).

Table questions

Tables are the densest format. They pack a lot of data into a small space, which means the main risk is reading the wrong row or column. Use your finger (or cursor) to track across rows.

Table trap
A table shows 2024 and 2025 revenue for five products. Product C grew from $3.2M to $4.0M. What is the growth rate?

Growth = (4.0 − 3.2) / 3.2 = 0.8 / 3.2 = 25%.

Common error: dividing by the new value (0.8 / 4.0 = 20%). Always divide by the base (starting) value.

Chart-specific traps

  • Bar charts: stacked vs grouped. Stacked bars require subtraction to get individual values.
  • Line graphs: the y-axis may not start at zero, exaggerating trends.
  • Pie charts: you often need to compute the underlying value from a percentage and a given total.
The 5-second unit check
Before calculating anything, spend five seconds confirming the units. “Thousands” vs “millions” is the single most common source of wrong answers in data interpretation questions.

Drill data interpretation on forge

323 data interpretation questions across SHL, AON, Cappfinity, and Forge — each tagged to a specific sub-skill.

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