Which design provides a causal conclusion but lacks random assignment?

• A. Descriptive
• B. Correlational
• C. Quasi-Experimental
• D. Experimental

Answer: (C)

When researchers want to claim a cause-and-effect relationship, random assignment is the strongest tool to make groups comparable and rule out alternative explanations. An experimental design uses random assignment and a control condition to clearly show that the intervention caused the observed changes. If random assignment isn’t possible, but the study still includes a comparison group or looks at outcomes before and after an intervention, it’s a quasi-experimental design. It can point to causality, but because the groups may differ in important ways from the start, other factors could explain the results. So this design provides a causal interpretation without random assignment, whereas descriptive describes only characteristics, and correlational studies identify associations without establishing causality.