Which design provides cause with random assignment?

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

Answer: (A)

Random assignment to different conditions is what makes experimental designs capable of addressing causality. By randomly placing students into an intervention group and a control group, any other variables tend to be balanced across groups on average. This means differences in outcomes after the program are more likely due to the program itself, not to preexisting differences. That balance strengthens internal validity and supports a causal interpretation of the results.

Other designs don’t include this randomization. Descriptive studies describe characteristics without manipulating anything. Correlational studies look at relationships between variables but do not involve manipulating an independent variable, so they can show associations rather than cause-and-effect. Quasi-experimental designs involve manipulation but lack random assignment, so initial group differences could influence results and causal claims are weaker.