Table 1

 Characteristics of National Collaborative Perinatal Project (NCPP) participants selected for follow up, interviewed, and included in the analytical sample

CharacteristicsSelected for follow up (%) n = 1062Full interviewed sample (%) n = 720Analytical sample (%) n = 633
*Birth weight less than 2500 grams. †Percentages do not total 100% because of missing data. ‡General eduation development degree (high school equivalency).
Any illness
Self perceived health
Full scale IQ, age 7
Low birth weight*
Learning disability
Socioeconomic status, age 7†
    Lowest quartile (0.2–2.5)23.524.223.8
    Middle-low (2.6–4.0)27.325.624.8
    Middle-high (4.1–5.6)
    Highest quartile (5.7–9.6)22.323.222.9
Attained education
    <High school18.217.5
    High school graduate19.920.7
    Beyond high school35.435.2
    College degree or more12.112.6