Two hand-hygiene regimens were compared by conducting a prospective randomized trial with a crossover design.
During phase 1 of the trial, nurses on each study ward were randomly assigned to use soap-and-water hand washing as currently practiced in the hospital or to disinfect their hands with an alcoholic hand gel.
When nurses reported for enrollment, the study nurse rolled a die, and those with odd numbers were assigned to the soap group, and those with even numbers were assigned to the alcoholic–hand-gel group.
Stratification was used to assure that a comparable number of nurses were assigned to the soap group or the alcoholic–hand-gel group on each ward.