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EPSO Numerical Reasoning study materials
EPSO Numerical Reasoning study resources

EPSO Numerical Reasoning: Table and Chart Interpretation: Absolute versus Relative Values

EPSO Numerical Reasoning · Work through your exam, one topic at a time.

All guide sections

Table and Chart Interpretation: Absolute versus Relative Values

EPSO presents data in tables, bar charts, line charts and pie charts, and the dominant error is reading a relative figure where an absolute one is asked for, or the reverse.

Core rules

  • Read the units first: thousands, millions, percentages, index points, per capita. Every subsequent number depends on it.
  • Absolute change is new minus old, in the table's units. Relative change divides that difference by the old value. "Which grew most" means relative; "which added most" means absolute.
  • Index numbers: a series rebased to 100 shows relative movement only. An index of 120 in 2021 on a 2020 base of 100 means +20%, but says nothing about absolute size unless the base value is supplied.
  • Stacked bars: read each segment's height from the top of the segment beneath it, not from the axis.
  • Pie charts show share of a total only. Recovering an absolute value requires the total.
  • Truncated axes on line charts exaggerate small movements; check where the axis begins.

Worked example

Two departments' spending, in € thousands: A rises from 400 to 440; B from 200 to 240. Which grew faster, and which added more?

Relative: A = 40/400 = +10%; B = 40/200 = +20%, so B grew faster. Absolute: both added €40k, so it is a tie. Indexed to 2020 = 100: A = 110, B = 120.

The three answers are all correct for different questions; the mark depends on which was asked. B's growth rate is twice A's even though the absolute increases are identical, which is exactly what the item is built to test.

Normalising

Per-capita or per-GDP figures allow comparison between countries or regions of different size. Where a table supplies totals and populations, the comparison wanted is usually the ratio, not the total.

Traps

  • Comparing percentage shares across rows whose totals differ.
  • Reading a stacked segment from the axis rather than from the top of the segment below.
  • Treating an index value as an absolute quantity.
  • Interpreting a 3-D pie chart by apparent area rather than by the labelled percentages.