what is the research design, and is it appropriate to the study?
There are four common types of research desigsn implemented in psychological research: experiments, quasi–experiments, correlational studies, and descriptive studies. These designs differ in terms of how strong of a causal conclusion can be made from the results:
- In an experiment, participants are randomly assigned to groups and the researchers manipulate independent variables.
- In a quasi–experiment, participants cannot (for reasons ethical or otherwise) be randomly assigned to groups but the researcher still manipulates the independent variables.
- In a correlational study, participants either are not, or cannot (for reasons ethical or otherwise) be randomly assigned to groups, and the researcher observes or measures two or more variables.
- In a descriptive study, the researcher isn't as interested in measuring and comparing variables, but rather in describing some phenomenon or process.
Causal conclusions can be drawn in very well designed and executed experiments and are sometimes drawn (with caution) in quasi–experiments, but cannot be drawn in correlational or descriptive studies. Very important to evaluating reports of empirical studies is determining whether the research design is appropriate for addressing the research questions.
