“If we want to reduce the amount of changes made at the end of our projects, then we need to find out the causes to so many changes, but that means we should do causal-comparative research.”
Nowadays they tell us that the Boston Massacre wasn’t really what it was claimed to be. What was the cause? There are times that we might feel discovering the cause of project problems might be just as unpopular as digging around in the Boston Massacre. But if you must, then do it right.
One of the most common research methods used in Integrated PM is the Causal-Comparative research method. It’s used to investigate possible cause-and-effect relationships by observing some existing consequence (effect) and searching back through the data for plausible causal factors.
This contrasts with the experimental method which collects its data under controlled conditions in the present.
Principal Characteristics: Causal-comparative research is "ex post facto" in nature, which means the data are collected after all the events of interest have occurred. The investigator then takes one or more effects (dependent variables) and examines the data by going back through time, seeking out causes, relationships, and their meanings.
Strengths: The causal-comparative method is appropriate in many circumstances where the more powerful experimental method is not possible. It is used when it is not always possible to select, control, and manipulate the facts necessary to study cause-and-effect relations directly.
It also can be used when the control of all variations except a single independent variable may be highly unrealistic and artificial, preventing the normal interaction with other influential variables.
Of course, with most project conditions, it is used when laboratory controls for many research purposes would be impractical, costly, or ethically questionable.
Note: The experimental method involves both an experimental and a control group. Some treatment "A" is given the experimental group, and the result "B" is observed. The control group is not exposed to "A" and their condition is compared to the experimental group to see what effects "A" might have had in producing "B." In the causal-comparative method, the investigator reverses this process, observing a result "B" which already exists and searches back through several possible causes ("A" type of events) that are related to "B."
Weaknesses: The main weakness of any ex post facto design is the lack of control over independent variables. Within the limits of selection, the investigator must take the facts as they are found with no opportunity to arrange the conditions or manipulate the variables that influenced the facts in the first place.
To the extent that the conclusions can be successfully justified against these other alternatives puts the investigator in a position of relative strength. The difficulty in being certain that the relevant causative factor is included among the many factors under study.
To reach sound conclusions, the investigator must consider all the other possible reasons or plausible rival hypotheses which might account for the results obtained.