Cumulative, human capital, and psychological risk in the context of early intervention: links with IQ at ages 3, 5, and 8.

This article examines the effects of risks for a sample of low birth weight children (2,001 to 2,500 g and family income-to-needs at 250% of the poverty threshold or less; n = 228) using data from the Infant Health and Development Program (IHDP, an experiment testing the efficacy of early intervention). Cognitive test scores (IQ) are assessed at 3, 5, and 8 years of age. Links with risks at each age point are examined using three different models-cumulative, human capital, and psychological risks. Similar decrements in IQ scores are found at all ages for the cumulative and human capital models but not for the psychological risk model. Treatment effects are found at 3 years of age (when the intervention ended) for all levels of risk and for all models. Sustained effects of the treatment were found at 5 and 8 years of age for children with moderate levels of human capital risk but were not found for any levels of psychological risk. Implications for early childhood intervention programs are discussed.