Control Group

Experimental Group

Example of a Two-Group Experiment: Technology in the Classroom

Logic of Causal Inference in Controlled Experiments

A researcher is conducting an experiment to determine if a new energy drink improves participants' performance on a complex puzzle. One group of participants drinks the new energy drink, while a second group drinks a similar-tasting beverage without the active ingredients. Both groups are then timed on how long it takes them to solve the same puzzle. For the researcher to validly conclude that the energy drink caused the observed difference in puzzle-solving times, which of the following is the most critical condition of the research design?

Factorial Design