The evaluation of legislative reforms on the motoring public is presumably backed by fundamental or primary data that is consistent for a number of years, and that is not generally contaminated. In the realm of motorcycle statistics a different story appears, because evaluations are based on primary data that is largely non-uniform, incomplete, and inconsistent across states. When experimental designs utilize this primary data at face value, the generalizations may be artifactual, and the investigation of that particular social reform may be seriously confounded. When clean and consistent data is combed from the existing masses the results may differ from generalizations based on unqualified data. Caution should also be applied to the uses of quasi-experimental designs for evaluating social reforms concerning motorcycling because of a different set of variables effecting the motorcycling experience. The recurrent topic of motorcycle helmet laws provides illustration.