I've been having this debate with a few other runners. I think it is fine to say you are a 4 minute miler if you have run the equivalent in a 1500; but to call yourself a sub 4 miler you must actually do it, unless your 1500 time equates to well under. Some of my friend think that even to call yourself a 4 minuter (not sub) you need to run it....but given that there are far more opportunities to run 15's I think it is fine to say you are a 4 minute miler but draw the line a little harder at the sub 4 title. Any thoughts on this...