How long should I wait to hear the job interview result!!!

#1

Hi,
I have given a face-to-face job interview at SAGA and it’s been almost 1 month, I haven’t heard from them. I don’t know if I should follow up or not? The interviewer said at the end of interview that it might take 3-4 weeks for the selection process. Then there is going to be another assessment. I wonder if I should keep on waiting or make an effort to follow up? I am getting impatient and please help if any one has gone thru this with SAGA.
thanx.