I believe that one of the worst things a loan officer can do is advise a borrower whether to lock or float. The loan officer that participates in this practice will almost always lose. Sure they might guess correctly a few times but ultimately this practice will come back to bite them in the butt. Predicting mortgage rates is kind of like trying to time the stock market, and nobody can ever time it perfectly. Instead of pretending to predict interest rates for their borrowers, good loan officers present the borrowers with the various options of floating vs locking for 15, 30, 45, 60 days, etc. and do so in such a way that the borrowers fully understand the risks of floating and the potential opportunity costs of locking.