The primary purpose of this study was to evaluate age-developmental differences in boys' incorporation of information about chronicity of a transgressor's behavior in their judgments of the efficacy of paternal disciplinary behaviors. Additionally, the study was designed to investigate boys' evaluations of fathers' applications of different types of discipline. A total of 157 Caucasian boys ranging from 5 to 16 years of age participated. The expectation was confirmed that 8- to 9-year-olds and 11- to 12-year-olds, but not 5- to 6-year-olds, would judge paternal disciplinary behaviors to be efficacious in preventing future transgression. However, the expectation that boys 11 to 12 years of age and older would incorporate "chronicity" information in their efficacy judgments was not confirmed. Additionally, contrary to predictions, 15- to 16-year-olds did not judge paternal disciplinary behaviors to be efficacious at all. Evaluations of the disciplinary fathers were, relatively, strongly negative at the 5- to 6-year age level and neutral to very good at all older age levels. However, only the 11- to 12-year-olds evidenced a significant relationship between their efficacy judgments of paternal discipline and their evaluations of the fathers. Findings are interpreted in terms of post-hoc evidence of boys' mediating conceptions derived from verbal interviews. (Author/MP)