Figures 2 and 3 show the association of the calculated PGS with final education (years of education and completed college) for different race and ethnicity. Since the the summary results from \citet{Okbay_2016}
are based on white European ancestry, the PGS we calculated has higher power in predicting educational attainment for White. Despite that, the association is clearly present also for Black and White Hispanics.
Neighbourhood characteristics
Neighborhood characteristics are based on contextual characteristics at
Wave I, reported as census block group level. Census blocks are defined
as “a small, usually compact area, bounded by streets and other
prominent physical features as well as certain legal boundaries.” A
block group is a cluster of census blocks within a census tract. It is
the lowest level of geography for which the Census Bureau publishes
sample data. For the 1990 Census, block groups averaged 452 housing
units, or 1,100 people. A typical census tract contains 4 or 5 block
groups. Once merged with genetic subsample, Add Health includes
information on 1,666 Census Blocks, 2,901 Census tracts, 220 counties and 37 States.
The following information at the block group level (measured in Wave I)
are used in the preliminary analysis:
-
Proportion individuals aged 25+ with college degree or more
- Prop individuals with income below poverty level
-
Proportion related children under 18 years in families with income in
1989 below poverty level, total and by family type
-
Unemployment rate.
- Proportion single mothers
- Log of median household income
Figures 4 and 5 show a strong association between neighbourhood characteristics and final educational attainment. To summarise the different components of neighbourhood quality, we constructed a "neighbourhood quality index" based on the first principal component of a principal component analysis based on the six above mentioned characteristics. A standardised index is used in the analysis.