Reasoning: Errors in Causation
Often writers argue that there is a causal relationship between two or more things. For example, some might argue that the high turnout of Evangelical voters in 2004 led to President Bush’s victory. Unfortunately, many writers make unwarranted logical leaps when portraying one event as the cause or effect of another. Described below are several kinds of common errors when writers discuss causality.
Correlation does not imply causation.
Many scholarly studies use the word “correlation” to describe two occurrences which happen together. A correlation, however, does not necessarily mean that the two events are logically connected, much less that one caused another. There are two specific errors one should keep in mind when discussing correlating events in academic papers.
Post Hoc, Ergo Propter Hoc.
This Latin phrase translates to “After this, therefore because of this.” Sometimes writers assume that because one event takes place before another, it must be the cause of it. While this situation is necessary for causation, it alone is not sufficient. Political science professor Dr. Erkulwater provides an example of what she sometimes sees:
This statement may or may not be true; the point is, one must have more information than simply the time the two events took place to assert that the former event caused the latter.
A related problem with establishing causality is that there could be more than one cause of an event. If one looks at data and finds that:
This observation, however, neglects the possibility that a third variable, Z, is also necessary for Y to happen. X alone does not cause Y; rather, X and Z together cause Y. Alone, either X or Z could be insufficient.
For example, sometimes economists use a person’s “willingness to pay” for a good to determine the demand for the good. Demand, however, is also determined by a person’s ability to pay for the good.