I believe you may have meant to ask about "causal" research design.
Causal research design is a type of research that involves investigating the cause-and-effect relationship between variables. The purpose of this design is to determine whether or not changes in one variable cause changes in another variable.
In a causal research design, there are typically two groups: a treatment group and a control group. Researchers manipulate the independent variable (the treatment) for the treatment group and keep it constant for the control group. They then compare the results of the two groups to determine if the independent variable caused a change in the dependent variable.
For example, let's say you want to study the effect of a new drug on reducing anxiety levels. You would randomly assign participants to two groups: one group would receive the drug (treatment group) and the other group would receive a placebo (control group). You would then measure their anxiety levels and compare the results to see if the drug had a significant effect on reducing anxiety.
Causal research design is often used in scientific studies and experiments, and it allows researchers to make inferences about the relationship between variables. It is important to note that causal research design does not always prove causation, as there may be other variables at play that could influence the results.