The objective of this study was to assess whether a mediated model of change could account for the long-term effects of infant home-visiting services observed at ages 5 and 7 years in a high-risk cohort. Participants were 41 mothers and infants from low-income families who were referred to parent–infant home-visiting services during the first 9 months of life due to concerns about the caretaking environment. Services ended when infants reached 18 months of age. Families received between 0 and 18 of weekly home visits based on infant age of entry into the study. During childhood (ages 5 and 7 years), teachers rated children's behavior problems using standardized instruments. Early home-visiting services accounted for positive child outcomes at 18 months, 5 years, and 7 years of age; however, earlier positive outcomes related to intervention did not account for intervention-related effects at later ages. Further inspection of the data revealed that two additional principles, one of escalating morbidity among less intensively served groups and one of generalized family problem-solving skills, were needed to account for the pattern of effects over time. We conclude that the “domino models” assessed by mediational analyses may be too simple to capture the intervention-related change processes occurring in high-risk cohorts over time.