Thus, this design allows both between group and within-group analyses. Moreover, it also allows flexibility in deciding when to initiate a stepwise increase in patients served and in augmenting the intervention strategy based upon problems and solutions identified over time. This design is particularly appropriate in implementing interventions like a hospitalist program for which there is likely clinical benefit with minimal risk, and it is not feasible for logistical or financial reasons to either randomize or deliver the intervention simultaneously to all participants.