Spurious Relation (or Correlation) (a) - A situation in which measures of two or more variables are statistically related (they cover) but are not in fact causally linked—usually because the statistical relation is caused by a third variable. When the effects of the third variable is taken into account, the relationship between the first and second variable disappears. Lurking Variable - A third variable that causes a correlation between two others - sometimes, like the troll under the bridge, an unpleasant surprise when discovered. A lurking variable is a source of a spurious correlation. An investigator who takes their correlation results as indicating a causal relationship is subject to a plentiful source of criticisms - the artifact of the third variable. If it be asserted from a significant correlation of A with B that A causes B. The critic can usually rebut forcefully by proposing some variable C as the underlying causal agent for both A and B. | ![]() |
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