TRANSLATION FORMULAS FOR NON-REPEATABLE EVENTS

Ryder's translation expressions for repeatable events are extended to the case of non-repeatable events. It is found that cohort quantum is a constant function of time when period quantum is constant, and perio d tempo, as measured by the moments of the age pattern of the occurren ce-exposure rates, change linearly with time. The degree of distributi onal distortion (that is, the upward or downward shift in cohort quant um caused by changes in the period age pattern), given a set of occurr ence-exposure rates, is generally less for non-repeatable than for rep eatable events in this case, in particular at high quantum levels. Fur thermore, it is found that when period tempo is constant over time, an d period quantum falls linearly, period quantum underestimates cohort quantum for high period quantum levels, and overestimates it for low p eriod quantum levels.