presence dependence the presence of data in a field only on condition that there is data present in a certain other field; p. d. complicates the estimate of the probability of the outcome of a comparison being a certain weight. An example is where the day of month is not normally present without the month also being present. The surname (maiden name) of a mother is usually not present unless her given name is also given. (Cf. value dependence, dependency chain, chain (2), adjusted presence.) [Cf. Ch. 5, §1, ¶1 especially Ch. 5, §2]