We address the problem of selecting the best of a set of units based on a criterion
variable, when its value is recorded for every unit subject to estimation, measurement,
or another source of error. The solution is constructed in a decisiontheoretical
framework, incorporating the consequences (ramifications) of the various
kinds of error that can be committed. The related problems of classifying
the units to a small number of groups and ranking them are solved by a similar
approach. An application is presented involving retention rates in the undergraduate
courses of a university.