Is there ever good correlation between any scores? You just never can tell from looking at the scores. The gymnast could have had an uncharacteristic good/bad day. The routines are different. The judges are different. Way too many variables.
I would say it's safe to say that a gymnast scoring 12's in 3 events, then say oh, 8.7-ish on bars, probably struggles on that event AND had a bad day.
From the sessions I watched, scores below a 9 was just short of a disaster of a routine, scores of 9.1-11.0ish usually reflected a fall (or two or three), scores of 11.5-12.0 for routines that weren't quite polished, 12.1-12.9 for a decent routine, scores 13.0+ was an awesome set! Of course, this is just for HOPES sessions.