Characteristics of Ex-Post Facto Research:

Based on the concept of the ex-post factor research, it is also known as ‘causal comparative research’. The ex-post facto research has certain characteristics which distinguishes it from other different types of research.

Some of these characteristics are presented below in the following paragraphs. The research has a control or a comparison group. As the research is done on the basis of the study of the cause which has already led to its effects, it becomes necessary for the researcher to keep a control group, which can be used for comparison with the actual experimental group later on, in order to analyse the cause of an already occurred event. The behaviour, action, event or the treatment or the independent variable of the research cannot be manipulated or changed. As the ex-post research is a kind of study which tries to predict the causes on the basis of actions that have already occurred, the researcher cannot manipulate or change the already occurred actions or behaviour.

The research focuses on the effects Since the researcher tries to analyse and predict the reasons behind the occurrence of an event or phenomena, their first attempt is to focus on the event or the phenomena that has already occurred. Only after having a detailed study of the phenomena or the event, the researcher tries to determine the causes behind such an event or phenomena.

The research tries to analyse the ‘how’ and ‘what’ aspect of an event Since the researcher tries to understand the causal effects behind a phenomena, the research basically focuses on how and what reasons that has led that phenomena to occur. Explores possible effects and causes With the help of an ex-post facto research, the researcher tries to analyse the cause and effect phenomena of an event, action or behaviour.

Differences: Ex-Post Facto Research – In this kind of research, the independent variable or variables have already occurred in.which the researcher starts with observation of a dependent variable or variables. He then studies the independent variables in retrospect for their possible relations to and effects on the dependent variable or variables. The most important difference between experimental research and ex-post facto research is control. In the former, the investigator has a manipulative control on the independent variable, whereas in the latter this control is not possible, more than this, randomization is not possible. In the ex-post facto research, the researcher must take things as they are and try to collect data and analyse them in that context.

In an ideal social scientific research, the possibility of finding random samples of subjects and randomly assigning them to groups and treatment to group would always be possible. However, these possibilities do not exist in the real situation. The ex-post facto research could be of a large scale or a small scale. This type of research has three weaknesses:
(1) the inability to manipulate the independent variables,
(2) lack of power to randomize, and
(3) the risk of improper interpretation.

In other words, compared to experimental research, other things being equal, ex-post facto research lacks control. This lack is a basis for the third weakness: the risk of improper interpretation. Therefore, committing unequivocally to experimentation or to ex-post facto research may be poor policy; Ex-post facto research may not have particular hypothesis as a predicted relationship may be quite spurious.

In true experimental research, participants are assigned to groups based on some criterion, often called the treatment variable or treatment condition. For example, you want to compare the effects of two different techniques for reducing obsessive-compulsive disorder behaviour in adults. The first technique includes behavioural therapy and the second does not. Once adults are assigned to groups and the programs are completed, you will want to look for any differences between the two groups with regard to the effects of the therapy on the number of obsessive-compulsive behaviours. Because assignment to the groups is determined by the researcher, the researcher has given assignment to the groups as determined by the researcher, and thus the researcher has complete control over the factors to which the adults are exposed.

From MPC-005 Research Methods – IGNOU