waiting time for h1b-visa rfe response review . please provide Info

On November 18,2016. my case status changed to “Response To USCIS’ Request For Evidence Was Received”.

However, after that 4 weeks has passed and still the status has not changed in USCIS website.

Some of my friends got the decision in a week.

Can anyone please let me know the reason for the delay from USCIS.(Is it due to Christmas holidays?)