Skills - Reading and Interpreting Maps, Graphs, Statistics, Chronologies, and Historical Sources
The Skills domain tests whether you can read maps, graphs, statistics, chronologies, and short sources accurately and skeptically. The exam rewards attention to units, scale, source provenance, and the difference between description and inference.
Core rules
For maps, check the scale, orientation, legend, and projection. Contours show elevation; closer contours mean steeper slopes. Thematic maps often use choropleths, where shading represents rates or totals-read the legend to know which. For graphs, identify the type, axes, units, and whether series share an axis. Index numbers show relative change from a base year, not absolute levels. Rates (per 100,000, per capita) allow comparison across different-sized populations; counts do not.
For statistics, ask who collected the data, for what purpose, and what is missing. Correlation is not causation; a third variable may explain both. For chronologies, anchor events to regimes or known dates and check for BCE/CE and century conventions. For historical sources, distinguish primary from secondary, identify the author's position and audience, and corroborate with other evidence.
Worked example
Country A has 10 million people and 1,000 reported cases; Country B has 1 million people and 500 cases. Which has the higher incidence? Convert to rates: A = 1,000 ÷ 10,000,000 × 100,000 = 10 per 100,000. B = 500 ÷ 1,000,000 × 100,000 = 50 per 100,000. B is higher. The reasoning: raw counts favor large populations, so compare per-capita or per-100,000 rates before ranking.
Traps
Do not read a graph's highest point as the largest rate if the axis is logarithmic or the series are indexed differently. Do not ignore a broken axis or a truncated y-axis. Do not treat a source's claim as fact because it is old or official. Do not confuse a change in reporting with a change in incidence. Do not assume a map's north is always at the top.