What defines the dependent variable in an experiment?

• A. The outcome measured; example: test score after different teaching methods.
• B. The factor deliberately manipulated; example: type of instruction.
• C. The constant used across groups.
• D. The time of day the test is administered.

Answer: (A)

The dependent variable is the outcome you measure to see the effect of the manipulation. In the example, the test scores after different teaching methods are what you measure to compare which method works better. The thing you deliberately change to test its effect is the independent variable—the type of instruction in this case. You also keep certain factors the same across groups (constants) to prevent them from influencing outcomes. The time of day the test is given could affect scores and would typically be controlled so it doesn’t bias the results. So, measuring the outcome—test scores after different teaching methods—best defines the dependent variable.