Comparison is the skill of explaining meaningful similarities and differences between historical developments. On AP US History, comparison can appear in multiple-choice questions, short-answer questions, DBQs, and LEQs. It is especially important when a prompt asks how two regions, movements, states, ideologies, or time periods were similar or different.

AP US History assesses Skill 5, Making Connections, in multiple-choice questions, at least one short-answer question, the DBQ, and the LEQ. The DBQ can draw from 1754-1980. LEQ choices usually cover 1491-1800, 1800-1898, or 1890-2001.

What Comparison Requires

A strong comparison answer uses the same category on both sides. If you compare the economy of one case to the politics of another, the argument becomes uneven. Better categories include political authority, labor systems, social hierarchy, religion, ideology, trade, empire, reform, technology, or foreign policy.

A useful comparison usually does three things:

Names both cases clearly.
Uses a shared category of analysis.
Explains why the similarity or difference matters.

Subject-Specific Examples

Chesapeake and New England colonies developed different labor systems, economies, and social patterns.
Federalists and Democratic-Republicans differed over federal power, political economy, and foreign policy.
Populists, Progressives, and New Dealers all pushed reform, but they targeted different problems and used different levels of federal power.

These examples work because they are not just topic pairs. Each one points toward a category you can analyze. For example, comparing two states by "government" is a start, but comparing the role of taxation, representative institutions, military power, and elite support is stronger.

Writing a Comparison Thesis

A comparison thesis should include both a similarity and a difference when the prompt allows it:

Although [case A] and [case B] were similar because [shared feature], they differed in [category] because [case-specific explanation].

If the prompt asks you to evaluate the extent of similarity or difference, make a judgment. Decide whether the similarities were more important than the differences, or whether one category mattered more than another.

Evidence Moves That Work

Build a quick chart with the same categories for both cases.
Choose evidence that directly supports the category you are comparing.
Explain the significance of the similarity or difference instead of stopping after a list.
Use contextualization to show why the cases developed in different circumstances.

Common Mistakes

Side-by-side summaries: Do not write one paragraph about case A and one paragraph about case B unless you connect them directly.
Uneven evidence: Both sides need specific evidence.
Vague categories: "They were different socially" is weaker than naming class structure, gender roles, racial hierarchy, religion, or migration.
No significance: Explain why the comparison helps answer a larger historical question.

Practice

Try this prompt: Compare the development of labor systems in the Chesapeake and New England colonies before 1754.

Make a chart with at least three categories. Then choose the category that gives you the clearest argument, not the category with the longest list of facts.