When testing theories, economics is disadvantaged compared to the natural sciences because
◦ it deals with human behaviour and thus is not open to empirical testing.
◦ economic variables do not change enough to provide reliable data for testing hypotheses.
◦ some economic variables are determined within the theory.
◦ economic hypotheses cannot be accepted with complete certainty, by contrast with the other sciences.
◦ it is usually not possible to conduct controlled experiments in economics, in contrast with certain other sciences.