A causal relationship exists when one event (cause) is necessary for a second event (effect) to occur. The order in which the two occur is also critical.

Example:

★ For intoxication to occur, there must be heavy drinking, which precedes intoxication.

★ Determining cause and effect is an important function of evaluation, but it is also a major challenge.

Causation can be complex:

★ Some causes may be necessary for an effect to be observed, but may not be sufficient; other factors may also be needed.

★ While one cause may result in a particular outcome, other causes may have the same effect.

Being able to correctly attribute causation is critical, particularly when conducting an evaluation and interpreting the findings.