Confounding Variable
LSAT glossary · Logical Reasoning
Definition
An unmeasured factor that independently influences both the supposed cause and the supposed effect, creating a misleading correlation. Identifying confounding variables is key to weakening causal arguments on the LSAT.
Confounding Variable in plain English
A confounding variable is a sneaky third factor that secretly drives BOTH things you're looking at, tricking you into thinking one caused the other. Classic example: ice cream sales and drowning deaths rise together, so you might guess ice cream causes drowning — but the hidden factor is hot weather, which independently makes people buy ice cream AND go swimming. On the LSAT, when an argument claims "X caused Y" just because they happened together, the fastest way to weaken it is to point out a confounder that could explain the whole pattern. Spot the lurking third thing, and the causal claim falls apart.
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Practice Confounding Variable
Which one of the following, if true, most seriously weakens the manufacturer's claim?
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