Social scientists have to use evidence to explain they dynamics of our economic, cultural and political lives. Powerful arguments use several kinds of evidence, and weak arguments use just one kind evidence. These are the four forms of evidence we use in supporting our claims.

1. Anecdotal Evidence

a. Provides weak support for an argument

b. Acts as a powerful counterexample for dismissing an argument

c. Describes one, or a few best instances all of the same type, general nature, or structure

An anecdote is a specific example, usually grounded in personal, secondary, or incomplete evidence. Obviously an anecdote cannot prove a general statement, so avoid treating a single case as proving a general point. An anecdote is especially unconvincing when it is a broad example being used to support or oppose a very narrow claim. And a single anecdote or counterexample is alone sufficient to disprove a general statement. A well-chosen anecdote, however, can be a counter-example that demonstrates how a claim must be modified or qualified. Anecdotal evidence often appears in journalism, or in short essays like book reviews or public scholarship where a writer wants to undermine someone else’s claim.

2. Testimonial Evidence

a. Provides moderately strong or supportive evidence

b. References an established or trustworthy authority

c. Can render rich empirical evidence about specific phenomena

In social science research, we are supposed to use well-established or credible citations and sources. The testimony of credible experts — or human subjects — can strengthen an argument. Still, researchers must almost always say why the reader should especially consider that person’s observations, ideas, and perspectives valuable. In setting up testimonial evidence you must provide credentials: details on your methods make your research credible; details on the people providing testimony makes them credible. But respectable credentials alone establish the fact that we should accept the testimony without question. You should know when experts disagree on an issue, and that one lone expert isn’t sufficient to establish a claim. Testimonial evidence appears in popular magazines, and journalism. In the social sciences, it provides the rich empirical evidence that comes from interview, participant observation and ethnographic research, especially if the researcher does a good job explaining methods choices and does the work of interpreting testimony for a reader in a serious, critical way.

3. Statistical Evidence

a. Provides moderately strong or supportive evidence

b. References evidence from experiments or large-scale data collection

c. Summarizes, indexes, or models general phenomena

In social research, statistical evidence can provide generalizable and transportable knowledge about broad phenomena and trends. On the way to producing statistical evidence, however, are a lot of important method and sampling decisions that impact how confident we can be about generalizations. Preparing statistical evidence often means reducing complexity, summarizing trends, and simplifying definitions. When you structure an argument with statistics, always report the source and explain its credibility. Since statistics from different sources may vary or conflict, give reports from multiple sources when possible.

4. Analogical Evidence

a. Provides strong or supportive evidence

b. Explains either by comparison to a known phenomenon or common metaphor

Analogies provide interest and illumination to a line of argument. Analogic evidence allows a researcher to explain a phenomena by comparing it to something that is already well known. It can also allow a researcher to use apply a well-understood metaphor to explain social structures and organizational functions. Researchers have to be cautious, however, when creating or using analogies. An analogy can help a researcher see causal connections, but rarely does it provide hard proof for someone who is already resisting the conclusion. And when poorly presented an analogy can be misinterpreted, or may be reinterpreted and used against the conclusion. Analogic evidence is especially useful for explaining new things, or offering new perspectives, because they illustrate rather than establish a point of view on other kinds of evidence. Many social science theories are actually just nicely applied metaphors. Analogic evidence can appear either in the literature reviews that set up a social problem or in the conclusions that help a reader interpret new findings.

For more, see Seech, Z. (1993). Writing philosophy papers. Belmont, Calif.: Wadsworth. This work can be cited as Howard, P. (2016). Types of Evidence in Social Research. Retrieved from This work is licensed under a Creative Commons Attribution — Non Commercial — Share Alike 4.0 International License.

Writer and prof @oiioxford. Cyber-optimistic musings, bots, fuzzy logic.

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