The fallacy of causal oversimplification (or sometimes "single cause fallacy") occurs when an arguer ignores a variety of causal factors in something. In the simplest cases, an arguer construes just one of several contributing causes of something to be its only cause.

Here is an example:

"The cause of car accidents is speeding. Therefore, to reduce accidents we need merely to do tougher enforcement of speed limits."

This ignores that a variety of other factors contribute to automobile accidents, such as drunk driving, tailgating, device use while driving, failing to signal, and many other factors. To name any one of these as "the" singular cause is to engage in causal oversimplification.

A general template of this fallacy is:

1. (Where A has contributing causes B, C, D, etc.) The cause of A is B.

2. Therefore, for determining how to manage or deal with A, all of our attention should be on B.