Source Analysis

History is not the past itself but the disciplined reconstruction of the past from surviving evidence. Source analysis is the foundational practice through which historians transform raw documents, artifacts, images, and oral testimonies into usable evidence. Without rigorous source analysis, historical claims rest on authority rather than evidence, and narrative replaces inquiry.

This skill covers four interconnected practices: classifying sources as primary or secondary, sourcing (interrogating authorship and context), corroborating claims across independent sources, and contextualizing evidence within its historical moment. Together these practices form the evidential backbone of all historical work.

Agent affinity: herodotus (chair, source criticism and historiographical method)

Concept IDs: hist-primary-secondary-sources, hist-sourcing, hist-corroboration, hist-contextualization

The Source Analysis Framework at a Glance

Practice 1 — Primary vs. Secondary Sources

Definition. A primary source is a document, artifact, or record created during or close to the period under study, by a participant or direct witness. A secondary source interprets, analyzes, or synthesizes primary sources from a later vantage point.

The classification is relational, not absolute. The same document can be primary for one inquiry and secondary for another. A 1920s history textbook is secondary for the events it describes but primary for studying how history was taught in the 1920s. Classification depends on the research question being asked.

Categories of Primary Sources

Categories of Secondary Sources

The Spectrum Problem

The primary/secondary distinction is not a clean binary. Some sources occupy intermediate positions:

• A memoir written decades after events is primary (authored by participant) but carries secondary-source problems (retrospective interpretation, hindsight bias).
• A newspaper editorial from 1863 is primary for Civil War-era opinion but secondary for the battlefield events it describes from reports.
• An archaeological survey report is secondary (interpretation of material evidence) but becomes primary for studying archaeological methods of its era.

Practical rule. Always state explicitly what question you are using the source to answer. The classification follows from the question, not from the source alone.

Practice 2 — Sourcing

Sourcing is the systematic interrogation of a document's origin. Before using any source as evidence, a historian must establish who created it, when, where, for what purpose, and for what audience. Sourcing is not optional — it is the prerequisite for all subsequent analysis.

The Five Sourcing Questions

1. Who created this source? What is the author's identity, social position, institutional role, and relationship to the events described? An enslaved person's account of plantation life carries different evidentiary weight than a slaveholder's inventory.

2. When was it created? Proximity to the event matters. A letter written the day of a battle differs from a memoir written thirty years later. Both are useful, but for different purposes.

3. Where was it created? Geographic proximity shapes what the author could have known. A London newspaper reporting on colonial events relied on delayed dispatches and intermediary accounts.

4. Why was it created? Every source has a purpose. A diplomatic dispatch aims to inform a government. A propaganda poster aims to mobilize a population. A diary entry may aim at self-reflection. Purpose shapes content.

5. Who was the intended audience? A private letter to a confidant may be more candid than a public speech. A petition addressed to a monarch follows formal conventions that constrain what can be said.

Worked Example — Sourcing a Document

Source: Letter from Abigail Adams to John Adams, March 31, 1776.

• Who: Abigail Adams, wife of a Continental Congress delegate, educated, politically engaged, managing family farm during his absence.
• When: March 1776, months before the Declaration of Independence, during active debate about independence and new government.
• Where: Braintree, Massachusetts — away from Philadelphia where Congress met, relying on correspondence for political news.
• Why: Personal correspondence maintaining a marital and intellectual partnership; also a deliberate intervention in political thought ("Remember the Ladies").
• Audience: John Adams personally, though Abigail likely knew letters might circulate among trusted correspondents.

Sourcing conclusion. The letter is valuable as evidence of women's political consciousness during the Revolution and of the domestic-political nexus in elite colonial families. Its private nature suggests candor, but its rhetorical sophistication suggests awareness of broader stakes.

Practice 3 — Corroboration

Corroboration is the practice of checking claims across multiple independent sources. No single source, however compelling, establishes historical fact on its own. Convergence of independent accounts strengthens a claim; divergence demands investigation.

Principles of Corroboration

Independence matters more than quantity. Three accounts derived from the same original report provide the strength of one source, not three. A newspaper article, a private diary, and an official report that each independently describe the same event provide genuine triangulation.

Disagreement is information, not failure. When sources conflict, the disagreement itself is evidence. It may reveal different vantage points, different stakes, or different biases — all of which illuminate the event.

Silence is evidence. When a source that should mention an event does not, the silence requires explanation. The absence of women's voices in most political archives before the 19th century does not mean women were politically inactive —