I am doing a regression on the big 5 personality traits, and how birth order affect those traits. First I am trying to build 5 variables based on surveys that captures those traits. I have thought about creating dummies for each question in the category (trait) and then taking the average, but some of the questions are highly correlated, so the weight would be wrong.
I have made a principal components analysis, which gives me four components with an eigenvalue over one. The problem is that none of them accounts for over 40 pct. Of the variance.
Is there some way that I can merge the four into one variable? It is the dependent variable, so there can only be one.
Otherwise do you have another idea of how the index can be constructed?