Definitions for "Ex post facto"
From or by an after act, or thing done afterward; in consequence of a subsequent act; retrospective.
An ex post facto law makes acts criminal that were not criminal at the time they were committed.
(ehx pawst FAHK-toh) Latin: retroactive; a law that is passed "ex post facto" is designed to punish actions that were not illegal at the time of passage. Such laws are banned in the U.S. under Article I of the Constitution.
analysis: In the correlational method of research, an attempt to reduce the third-variable problem by picking people who are matched on characteristics that may be confounds.