Refers to the inability to legitimately deduce a cause-and-effect relationship between two variables solely on the basis of an observed association or correlation between them/

For any two correlated events, A and B, the different possible relationships include[citation needed]:

  • A causes B (direct causation);
  • B causes A (reverse causation);
  • A and B are consequences of a common cause, but do not cause each other;
  • A and B both cause C, which is (explicitly or implicitly) conditioned on;
  • A causes B and B causes A (bidirectional or cyclic causation);
  • A causes C which causes B (indirect causation);
  • There is no connection between A and B; the correlation is a coincidence.