Is the difference between an OLS regression and a GLS regression qualitative or quantitative?
It is quantitative
Ordinary least squares is a technique for estimating unknown parameters in a linear regression model. OLS yield the maximum likelihood in a vector
Generalized least squares allows this approach to be generalized to give the maximum likelihood estimate
Note the formulation for the two approaches results in real structural and quantitative difference. Notice the two are governed by two different Gauss distribution the