“…There is an extensive literature documenting the impact of individual biologic and socioeconomic risk factors on child development and school performance, and a growing literature on the developmental effects of urban neighborhood conditions e.g., Brooks-Gunn, Duncan, & Aber, 1997! At the individual level, the impact of biomedical and psychosocial influences on intellectual development appears to be cumulative~Dunst & Trivette, 1994;Sameroff, Seifer, Barocas, Zax, & Greenspan, 1987!, accounting for a significant proportion of the variance in school outcomes e.g., Goldberg, McLaughlin, Grossi, Tytun, & Blum, 1992!. Garbarino estimates that as many as 20% of American children experience a major accumulation of risk, including poverty, single-parent households, low parental education, and other social disadvantages~2001!.…”