Background
In a recent article,[1] the author introduced an a priori approach to assessing whether sufficient opportunity exists for a disease management program to demonstrate financial effectiveness; in other words, performing an analysis before the implementation of a program. A number-needed-to-decrease (NND) analysis was developed to estimate the number of condition-specific hospital discharges and/or emergency department visits that must be reduced in order to achieve various levels of return on investment in a given program year. In this paper, the NND analysis is analogous to the concept of the ‘number needed to treat,’ which is used in research to assess the effect of treatment in terms of the number of patients needed to be treated with a particular therapy to prevent one adverse event.