Page "Correlation does not imply causation" Paragraph 21

There is a relation between this subject-matter and the Ecological fallacy, described in a 1950 paper by William S. Robinson.

Robinson shows that ecological correlations, where the statistical object is a group of persons ( i. e. an ethnic group ), does not show the same behaviour as individual correlations, where the objects of inquiry are individuals: " The relation between ecological and individual correlations which is discussed in this paper provides a definite answer as to whether ecological correlations can validly be used as substitutes for individual correlations.

They cannot.

" (...) "( a ) n ecological correlation is almost certainly not equal to its corresponding individual correlation.