COMPARING CONTEMPORANEOUS LABORATORY AND FIELD EXPERIMENTS ON MEDIA EFFECTS

Researchers employing experiments often conduct their studies in the laboratory or in the field. Each mode has specific advantages (e.g., the control of the lab versus the realistic atmosphere of the field). Two hypotheses concerning the relationship between treatment effects in lab and field settings were tested in contemporaneous experiments. Registered voters in a medium-size city were randomly assigned to a laboratory or a field experiment involving newspaper stimuli. The analyses show significantly larger treatment effects in the laboratory experiment, especially for public opinion outcomes in which the content of the treatment could be readily linked to the dependent variable. Evidence also suggests that differences in the size of treatment effects moderate as lab and field experiments become similar on one dimension-namely, the temporal distance between stimulus and outcome.