How to Judge a History Source
The Detective's Toolkit: Core Concepts for Source Evaluation
Before you can solve a case, you need to know your tools. Historians use specific terms and ideas when they examine sources. Understanding these is the first step to becoming a great history detective.
Let's define the three main ideas from our summary:
- Usefulness: This asks, "Does this source help me answer my specific question?" A source about ancient Roman plumbing might be incredibly useful for a project on engineering, but not at all useful for a project on Roman music.
- Reliability (or Credibility): This asks, "Can I trust what this source says?" To figure this out, detectives look at where the source came from (its origin) and why it was made (its purpose).
- Limitations: This asks, "What are the problems or weaknesses of this source?" Every source has them. A diary is a personal view, not a general one. A photograph only shows one moment from one angle. Recognizing limitations stops us from making mistakes.
Two of the most powerful tools for checking reliability are analyzing a source's origin and purpose. We can organize our questions about them like this:
| Origin (Where does it come from?) | Purpose (Why was it made?) |
|---|---|
| Who created it? | Was it meant to inform, persuade, entertain, or record? |
| When and where was it created? | Who was the intended audience? The public, a friend, the government? |
| Is it a primary or secondary source?[1] | Does the creator have a reason to be biased or to hide the truth? |
From Clay Tablets to TikTok: Types of Historical Sources
Historical sources come in all shapes and sizes. They are usually split into two big categories: primary and secondary sources. Think of primary sources as eyewitness accounts, and secondary sources as reports written by someone who heard the story later. Both are important, but they are used differently.
Primary Sources: These are original materials created at the time of the event or very soon after. They offer a direct, first-hand connection to the past.
Examples: Letters, diaries, speeches, photographs, official documents (like treaties or birth certificates), artifacts (like tools or clothing), newspaper articles from the time, videos, and audio recordings.
Secondary Sources: These are created later by people who were not direct participants. They interpret, analyze, or summarize primary sources.
Examples: Textbooks, history books, documentaries, biographies, websites like encyclopedias, and articles written by historians.
Sometimes, a source can be both primary and secondary, depending on the question you're asking. A history book written in 1950 about the American Civil War is a secondary source for learning about the war. But for a historian studying how people in 1950 viewed the Civil War, that same book becomes a primary source! It reveals the attitudes of the 1950s.
A Real Case Study: The Mystery of the "Boston Massacre"
Let's apply our detective skills to a famous event in American history. On March 5, 1770, British soldiers fired into a crowd in Boston, killing five colonists. But what really happened? Was it a ruthless "massacre" or a chaotic act of self-defense? Historians must evaluate conflicting sources.
Two key pieces of evidence are the famous engraving by Paul Revere and the court testimony from the British Captain, Thomas Preston.
| Source | Origin & Purpose | Usefulness | Reliability & Limitations |
|---|---|---|---|
| Paul Revere's Engraving ("The Bloody Massacre") | Origin: Made by Paul Revere, a patriot and silversmith, just weeks after the event. He copied another artist's work. Purpose: Propaganda. It was designed to be printed and sold to stir up anti-British anger. | Extremely useful for understanding how patriot leaders wanted people to see the event. It shows us the power of images in shaping public opinion. | Low reliability for factual details. It shows soldiers lined up and an officer giving an order to fire (likely false). The scene is staged and emotionally charged. Limitation: It's not an accurate visual report; it's a political cartoon. |
| Captain Preston's Court Testimony | Origin: Created by Thomas Preston, the British officer in command, for his trial months later. Purpose: To defend himself and his men. His goal was to prove they acted in self-defense to avoid execution. | Very useful for understanding the British soldiers' perspective. It provides specific details about the chaotic crowd, thrown objects, and the fear of the soldiers. | Moderate reliability, but with clear bias. He has a strong motive to lie to save his life. However, some parts of his story were supported by other witnesses. Limitation: It's a one-sided account from a person under extreme pressure. |
| A Modern History Textbook | Origin: Written by historians in the 21st century. Purpose: To educate students by providing a balanced summary based on research of many primary sources. | Very useful for getting a general, well-researched overview of the event, its causes, and its effects. It's a great starting point. | Generally high reliability if from a reputable publisher. It synthesizes many viewpoints. Limitation: It is an interpretation, not a direct witness. It may simplify complex details, and even textbooks can have subtle biases. |
The lesson? A good detective never relies on just one witness. By comparing Revere's image (patriot propaganda) with Preston's words (a soldier's defense), and then checking them against other sources like trial records or letters from neutral observers, historians can piece together a more complete and truthful story: a tense, confused street fight that was cleverly used as propaganda to fuel a revolution.
Important Questions
A: Not necessarily. Age alone doesn't make a source reliable. A primary source from the time can be full of lies or mistakes. A modern secondary source, based on decades of research and newly discovered evidence, can often provide a more accurate and reliable account than a biased account written at the time. The key is to evaluate the source's origin and purpose, not just its age.
A: Use the same detective skills, but be extra careful! Ask: Who runs this website? (Look for ".edu", ".gov", or reputable museums). What is the author's qualification? When was it last updated? Does it cite its sources? Be very wary of sites trying to sell you something or push a strong political view without evidence. A viral historical "fact" on social media is often a primary source for studying modern myths, but a very unreliable source for learning about the past.
A: This is common and is where history gets interesting! Your job is not to pick one as the "winner," but to understand why they disagree. Could it be different perspectives (a general vs. a soldier)? Different experiences (someone inside an event vs. outside)? Different purposes (a private letter vs. a public speech)? The disagreement itself is valuable evidence about the complexity of the past.
Footnote
[1] Primary Source: An original document, recording, or artifact created at the time under study. Secondary Source: A work created later that discusses, interprets, or analyzes primary sources.
[2] Bias: A preference for or against something that influences judgment, often in an unfair way. All sources have some bias; the key is to identify it.
[3] Propaganda: Information, especially of a biased or misleading nature, used to promote a particular political cause or point of view.