Here the year by year issue of U.S. patents since 1836 is used to correct for growth their apparent aging, as obtained by a synchronous study of citations made by (a) U.S. patent examiners and (b) periodicals. Apparent and corrected aging are treated in terms of conditional probabilities. (Author)

Proposes a probabilistic mechanism to describe various forms of the Bradford phenomenon reported in bibliographic research. The inclusion of a time parameter in the model to allow predictions of dynamic systems is explained. (58 references) (CLB)