Historical inquiry, sources and quantitative evidence
What the domain tests
Interdisciplinary Social Studies Skills and Analysis tests how you read and reason with social studies sources: documents, data displays, maps, timelines, and descriptions of cartoons. You must identify claims, evaluate credibility, interpret quantities, recognize context, and distinguish causation from correlation.
Core concepts
- Sourcing: Ask who made the source, when, where, for what audience, and for what purpose. A primary source comes from the period; a secondary source interprets it later. Bias does not automatically make a source false, but it shapes emphasis and omission.
- Close reading: Separate the author’s claim from supporting evidence. Notice tone, figurative language, and what is left out. A fact can be checked; an opinion expresses a judgment.
- Data displays: Read the title, units, labels, legend, and scale before the numbers. Compare absolute amounts carefully with percentages. A rise from 10% to 15% is 5 percentage points, but a 50% relative increase. Check whether a sample is representative.
- Maps: Use the legend, scale, and orientation. Projections distort area, shape, distance, or direction; no flat map preserves all. Thematic maps show patterns such as population density or climate, not necessarily causes.
- Chronology and causation: Distinguish immediate triggers from long-term causes and necessary from sufficient conditions. Corroborate one source with another before drawing a strong conclusion.
Worked example
A table reports turnout in one election by age: 18–24, 38%; 25–44, 52%; 45–64, 66%; 65 and older, 71%. Which conclusion is best supported? The answer is that turnout was higher among older age groups in this table. Reasoning: the percentages rise with age. The table does not prove that age causes turnout, does not describe other elections, and does not show that 71% of all voters were 65 or older. Those claims go beyond the data.
Traps that cost marks
Do not ignore units, scales, or whether a figure is a percentage or a count. Do not treat a map as a neutral photograph; projections and legends shape meaning. Do not choose an answer because it is historically true if it does not answer the question about the source. Avoid assuming that because two trends move together, one caused the other. A single vivid source may illustrate a view without proving it was typical.
Key terms to recognize
Primary source, secondary source, corroboration, bias, point of view, correlation, causation, percentage point, projection, and periodization.