The variable measured in an experiment or study; what the experimenter measures.

When conducting research, a psychologist typically takes two or more similar groups of people or animals and exposes them to different treatments or situations. Then the researcher monitors a behavior of interest to see whether that behavior differs from one group to the next. This measurement is the dependent variable. A single experiment may involve more than one dependent variable.

When specifying the dependent variable, it must be clearly defined and measurable. In one experiment, researchers gathered a group of business executives who displayed evidence of Type A behavior (e.g., nonstop working, aggressiveness, and competitiveness). The researchers divided the executives into subgroups and either exposed them to a small amount of...