Ex-post Facto Research

A Detailed Guide for PhD Students on Ex-post Facto Research


So, you are a PhD student who is going to conduct his research soon, huh? Well, it is good to know you are finally approaching the end of your degree. As you are here, it is pretty clear that you have chosen an ex-post facto research design to study the problem, and you do not know much about it. Well, there is no need to worry because you have come to the right place. In today’s post, we will be talking about this important research design, its procedure, and some of its main advantages. Before that, let’s define this research design.

What Is An Ex-Post Facto Research Design?

An ex-post factor design is a quasi-experimental research design. It examines how an independent variable, which is already present in the participants, affects the dependent variable. So, it means that there is something in the participants that you do not have to alter, and that is their characteristics. For example, you are interested in measuring the effect of weight on the self-esteem levels of students. For this, you divide the participants into different categories, normal weight, underweight, and overweight, and then study them. This research study is ex-post facto research because weight is the independent variable that you cannot control or alter.

How To Conduct An Ex-Post Facto Investigation?

From the discussion above, it is now clear that ex-post facto is a quasi-experimental design in which you do not have control of the independent variable. The variable is pre-defined, and you cannot alter it. Despite this, there are some steps that you need to follow when conducting this investigation. A brief description of all those steps is as follows:

1. Define The Problem And Research It

The first step in this investigation is to define the problem. Defining the problem means identifying the issue first and knowing what to do in the study. When you define the problem, you get to know about your research purpose and its aims. Also, you get a preliminary idea of the independent and dependent variables. Along with defining the problem, you must also research it and try to find the relationship between the variables.

2. State The Hypothesis

This second step is the most important one in ex-post facto research. When you have identified your independent and dependent variables, you must state the hypothesis based on which you will carry out the research. The hypothesis is basically the research question that you are trying to answer. It develops a relationship between the variables, and you test the hypothesis to either approve or disapprove of it.

3. Select The Subjects, i.e., Sampling

Step no. 3 in ex-post facto research is about selecting the right samples or research participants. It is important to note here that, like experimental designs, this research design does not employ a random selection of participants. In fact, it selects the participants who have the defined characteristics. All the participants are grouped based on certain traits and characteristics. Hence, selecting the right subjects is the third step.

4. Gather The Data

Once you are done with defining the problem, research, hypothesis formulation, and sampling, it is time to gather the data to either approve or disapprove of the hypothesis. To do this, you must study all the selected participants in terms of the change that occurred in the dependent variable when the independent variable is constant. You must gather data for each category of the samples, which you have defined in the previous step.

5. Analyse, Interpret And Report The Results

After the data collection, the last step of ex-post facto research is to analyse that data using an appropriate analysis method. Based on your data type, you can either use qualitative or quantitative analysis methods. Once analysed, interpret the analysis results and report them. When interpreting the results, make sure to go back and see your research question or hypothesis. However, if you feel any difficulty in the analysis, you can get PhD dissertation help from different writing services.

Advantages Of Ex-Post Facto Research Design

Like the experimental design, this quasi-experimental design also has some advantages. A brief description of its advantages is as follows:

  • This research design is more useful where a very rigorous experimental approach to the research problem is not possible.
  • It allows the researchers to know what goes with what and under what conditions.
  • One of the main advantages of ex-post facto research is that it is very useful when you try to find the causal relationship.


Conclusively, ex-post facto research is a quasi-experimental research design that establishes a causal relationship between independent and dependent variables. To perform this research, you must make sure that you follow all the steps mentioned above. The advantages of this method also make it a good research method where you cannot control the variables.