[radmuzom]

> but this says that <2 years of experience is better than longer

When you say better, do you mean risk or return? First of all, you are looking at the variable in a "univariate" sense,i.e, the relationship of the default rate or return by the categories of this variable. But their internal model is multivariate - there may be other factors influencing risk or return which is not obvious in the univariate dimension. It also depends on the power of this variable in predicting risk. And finally, lower risk may mean lower return - you just need to find the efficient frontier :) - http://www.investopedia.com/terms/e/efficientfrontier.asp.