<Li> There is no connection between A and B; the correlation is a coincidence . </Li> <P> Thus there can be no conclusion made regarding the existence or the direction of a cause - and - effect relationship only from the fact that A and B are correlated . Determining whether there is an actual cause - and - effect relationship requires further investigation, even when the relationship between A and B is statistically significant, a large effect size is observed, or a large part of the variance is explained . </P> <P> Reverse causation or reverse causality or wrong direction is an informal fallacy of questionable cause where cause and effect are reversed . The cause is said to be the effect and vice versa . </P> <Dl> <Dt> Example 1 </Dt> <Dd> The faster windmills are observed to rotate, the more wind is observed to be . </Dd> <Dd> Therefore wind is caused by the rotation of windmills . (Or, simply put: windmills, as their name indicates, are machines used to produce wind .) </Dd> </Dl>

Reverse causality problem in determining cause and effect