coefficient for reading of B = .19 (p <.001) is less than half the size of the 3rd quartile
coefficient for reading in the original study, B = .49 (p < .001). For the combined
math/reading variable the coefficient of B = .38 (p < .001) in the new study is
approximately one-third the size of the standardized coefficient for the combined
math/reading variable in the original study, B = 1.07 (p < .001). Dropping to the 2nd SES
quartile yields a standardized coefficient for reading scores of B = .11 (p < .001) in the
new study compared with a coefficient of B = .28 (p < .001) in the original study.
While none of the standardized regression coefficients in this model are particularly
strong, it is worth noting that standardized regression coefficients are reduced by half for
each progressively lower SES quartile, relative to the reference group. There is a near
linear trend for SES on math achievement. Unstandardized coefficients for the 1st wave
follow-up math score are b = 4.41, (p < .001) for the 2nd quartile, b = 7.53 (p < .001) for
the 3rd quartile, and b = 12.42 (p < .001) for the 4th quartile. For those in the 4th quartile,
each one point increase on the SES scale is associated with an increase of 12.42 points on
the 1st wave follow-up math score, after controlling for all other independent variables in
the regression model.
With standardized regression coefficients that are very similar to the original study,
parental checking-up on their students’ academic activities yields statistically significant,
negative effects. For the parental checking-up variable, standardized coefficients include
B = -.05 (p < .001) for the math score; B = -.04 (p < .001) for the combined math/reading
score; and B = -.03 (p < .001) for the reading score.