Professors Even and Macpherson are able to infer from these differences in treatment that the three-stage minimum wage increase led to a reduction in teenage employment of 6.9% (about 98, 000 jobs) in the nineteen states affected by all three stages.
Naturally, the smart marketer wants to build marketing funnels which provide the cheapest, most economical transition from one stage to the next, while keeping customer loss to a minimum.