What role does the independent variable play in an experiment?

The independent variable is crucial in an experiment as it is the factor that researchers intentionally manipulate or change. This alteration allows them to observe its effects on the dependent variable, which is the outcome being measured. By controlling the independent variable, researchers can establish a cause-and-effect relationship and determine how variations in the independent variable influence the results.

The other options refer to different concepts in experimental design. Keeping a variable constant relates to the control variables, ensuring that they do not interfere with the results. The outcome being measured corresponds to the dependent variable, which is the result that researchers are interested in predicting or observing. Lastly, measuring the success of the experiment pertains more broadly to the assessment of experimental results rather than the function of the independent variable itself.