Four strategies used in judgment patterns were explored. Problem sets in which each solution strategy produces a unique solution pattern are depicted. Several experiments had been conducted using rules in this way with subjects from grade 4 through college. Problems were set in the context of concrete events which could be related, and subjects were asked about the relative likelihood of an outcome. A strong developmental trend was found, with students using increasingly sophisticated rules with increasing age. Current efforts are focused on trying to account for trends, noting knowledge differences between age groups that may be implicated in the differences in rule use. An experiment to train seven-year olds to use the a-versus-b rule is described; this was successful. Next, students in grades 4, 5, 7, 8 were trained to use the sum-of-diagonals rule, again successfully. (MNS)