The crudest outcome measure, and the one most widely used, is donors per million population (DPMP). It requires the assumption that potential donors are more or less equally distributed over a population, so that the population itself can be used as a rough proxy of the potential donor pool. The calculation of this measure is the easiest of the three outcome measures described here, requiring only census data and the number of donations in a specified geographical area.
- While the simplicity of this approach has made it the most recognized of measures, including use internationally and by the US DHHS in OPO certification, the use of unadjusted population size raises significant methodological problems. For example, any state with higher than average proportions of residents older than the allowable age for donation (e.g., Florida) or with a lower than average rate of trauma death will have an artificially high denominator in the DPMP rate, thus deflating its true procurement efficiency with "potential donors" who can’t be realized. Despite the ease of calculating DPMP, its lack of comparability across geographic borders compromises its utility for meaningful evaluation.