The statistical fate of a group of individuals who are subject to a process of ‘wastage’ forms the theme of an important class of actuarial problems. Usually the rates of the several individual sources of wastage are relatively complicated functions of such variables as age, duration, or rank, and the full apparatus of the service table must be employed. In other cases, however—including some of practical importance—these functions degenerate, in fact or in supposition, into constants, and a simpler approach accordingly becomes possible. By considering the operation of wastage—which includes such events as death, breakdown of health, resignation, and discharge—as equivalent to the financial operation of discounting, a formal identity can be created between certain ‘manpower’ problems and corresponding problems involving compound interest; and numerical work on the former is much simplified by the use of tables of common compound interest functions.