Children's fuzziness leads to increased variance in the data, data loss, and high dropout rates in developmental studies. This study investigated the importance of 20 factors on the person (child, caregiver, experimenter) and situation (task, method, time, and date) level for the data quality as indicated via the number of valid trials in 11…

This study shows that residual variation can cause problems related to scaling in exponential random graph models (ERGM). Residual variation is likely to exist when there are unmeasured variables in a model--even those uncorrelated with other predictors--or when the logistic form of the model is inappropriate. As a consequence, coefficients cannot…

In studies of educational achievement, students' self-reported number of books in the family home is a frequently used proxy for social, cultural, and economic background. Absent hard evidence about what this variable captures or how well, its use has been motivated by strong associations with student outcomes. I show that these associations rest…