Ex post ( Latin for “afterwards”) is a term used in legal technical language and describes the assessment from a retrospective point of view. The viewer is also aware of later processes that could not have been known at an earlier point in time. Assessment ex post is the opposite of assessment ex ante (“from before” or “from the start”).
In empirical research , one speaks of an ex-post-facto design or a non-experimental design. In contrast to experimental design or quasi-experimental design, one does not change the situation, but only looks at a state “in retrospect”.