What is an example of ex post factor research?

Answer 1

Ex post facto research

When translated literally, ex post facto means ‘from what is done afterwards’. In the context of

social and educational research the phrase means ‘after the fact’ or ‘retrospectively’ and refers to those studies which investigate possible cause-and-effect relationships byobserving an existing condition or state of affairs and searching back in time for plausible causal factors. In effect, researchers ask themselves

what factors seem to be associated with certain occurrences, or conditions, or aspects of behaviour.

Expost facto research, then, is a method of teasing out possible antecedents of events that have happened and cannot, therefore,be engineeredor manipulatedbythe investigator.The following examplewill

illustrate the basic idea. Imagine a situation in which there has been a dramatic increase in the number offatal road accidents in a particular locality. An expert is called in to investigate. Naturally, there is no way in which she can study the actual accidents because they have happened; nor can she turn to technology for a video replay of the incidents. What she can do, however, is attempt a reconstruction by studying the

statistics, examining the accident spots, and taking note of the statements given by victims and witnesses. In thisway theexpert willbe ina position toidentify possible determinants ofthe accidents. These may

include excessive speed, poor road conditions, careless driving, frustration, inefficient vehicles, the effects of drugs or alcohol and so on. On the basis of her examination, she can formulate hypotheses as to the

likely causes and submit them to the appropriate authority in the form of recommendations. These may includeimproving roadconditions,orlowering thespeedlimit, orincreasing police surveillance, for

instance. The point of interest to us is that in identifying the causes retrospectively, the expert adopts an ex post facto

perspective.

Kerlinger (1970) has defined expostfacto research moreformally asthat inwhich theindependent

variable or variables have already occurred and in which the researcher starts with the observation of a dependent variable or variables. She then studies the independent variable or variables in retrospect for their possible relationship to, and effects on, the dependent variable or variables. The researcher is thus examining retrospectively the effects of a naturally occurring event on a subsequent outcome with a

view to establishing a causal link between them. Interestingly, some instances of

ex post facto

designs correspond to experimental research in reverse, for instead of taking groups that are equivalent and

subjecting them to different treatments so as to bring about differences in the dependent variables to be measured, an ex post facto experiment begins with groups that are already different in some respect and searches in retrospect for the factor that brought about the difference. Indeed Spector (1993:42) suggests that ex post facto

research is a procedure that isintended to transform a non-experimental research design into a pseudo-experimental form.