Omitted variable bias occurs in most statistical models. Whenever a confounding variable that is correlated with both dependent and independent variables is omitted from a statistical model, estimated effects of included variables are likely to be biased due to omitted variables. This issue is particularly problematic in physics education research…

Dealing with data from multiple family members presents problems for researchers, as many of the techniques available for dealing with such data are problematic, and there is no way that is unique to each family. Proposes and gives an example of the use of Q factor analysis as a means of combining data from multiple family members in a unique way…