Conditional Independence in a Binary Choice Experiment

Experimental and behavioral economists, as well as psychologists, commonly assume conditional independence of choices when constructing likelihood functions for structural estimation. I test this assumption using data from a new experiment designed for this purpose. Within the limits of the experiment’s identifying restriction and designed power to detect deviations from conditional independence, conditional independence is not rejected. In naturally occurring data, concerns about violations of conditional independence are certainly proper and well-taken (for well-known reasons). However, when an experimenter employs contemporary state-of-the-art experimental mechanisms and designs, the current evidence suggests that conditional independence is an acceptable assumption for analyzing data so generated.