Data Interpretation and Analytical Skills
Data Interpretation and Analytical Skills tests whether you can read tables, bar and line charts, and pie charts and then compute rather than eyeball. Questions usually ask for a rate, a share, a ratio, or a comparison between two periods.
Core rules
- Read the axis units and the base year before calculating; a chart starting at 80 rather than zero exaggerates visual differences.
- Pie charts show shares, not absolute values. A segment can grow in percentage while shrinking in absolute terms if the total falls.
- Growth rate = (later − earlier) ÷ earlier. For multi-year compound growth, use the geometric mean, not the arithmetic average of yearly rates.
- Percentage-point changes describe shares; percent changes describe relative movement.
- When comparing ratios across categories with different totals, convert to a common base (per 1,000 or per capita).
- Approximate before computing: round to two significant figures to eliminate options, then compute only if two remain.
Worked example
A department's spending rose from 500 to 600 (a 20% increase). Its training share fell from 20% to 18%. Training spend was 100, then 108 - the share fell by 2 percentage points while the amount rose 8%. A question asking "did training spending fall?" is answered no; a question asking about priority is answered yes, since training lost share.
Traps
Confusing percentage with percentage points; reading a pie chart as absolute; using arithmetic means for compound growth; ignoring a change in the total when comparing segments; and answering from visual impression when the numbers contradict it.