General Question

[Aamir Khan]

Hello,
Kindly let me know why it is recommended to use OLS and Fixed effect model before using GMM. Is it a good practice to use GMM directly instead of using OLS and Fixed effect.

[Carlo Lazzaro]

Aamir:
never heard about that advice (but it may well be my fault).
My guess is that GMM, despite it's greater flexibility, it's more difficult that the usual regression tools (and this might be the reason why they're ranked last in the advice you report).