I thought it would be obvious to tell the difference between a ball that has rolled out vs a ball that never entered the roll stage.  However, in the wet-dry era of the THS, it isn't quite as obvious as I thought.  Through the pins, they both look similar in that the ball deflects and the end result is bad carry.

For a tweener like me, I'll try to control the reaction to settle down the over-under especially when it seems like a miss right goes high and a miss left doesn't get to the pocket.  In doing this, the ball doesn't make much of a pronounced breakpoint.  Recently, when I've seen bad carry, I've moved everything in and slowed down to allow time for the ball to roll.  This has worked, but I did it later than I should have because I thought the ball was rolling out in the dry.  But in retrospect I think it wasn't getting into a roll in the wet/carrydown.  This happens most often during the transition when the oil line isn't as obvious and the backends aren't fresh.

I feel like I should be able to adjust quicker than I am given I've bowled for a long time now, but I'm just not seeing it soon enough.

Where and what do you look for to determine if a ball has rolled out?  What are solutions?

Where and what do you look for to determine if a ball has not started to roll?  What are solutions?

It's hard to explain, but basically when a ball has lost energy and is rolling out, it will stop continuing and roll on a straight line in the direction of its rotation.  If it's not rolling, there are a few different ways it can appear to be rolling (or not rolling rather, lol) depending on a few different factors.  And it IS rather hard to see because a ball can be revving and flaring, but never roll before it hits the pins. 

First, you point is well taken.  In the old days of rubber and polyester balls, rollout was totally obvious, because you could really see the hook stop move.  Two things make it much harder to see with modern balls.  First, the entry angle can still be very steep, and come very late on a roll out shot with modern balls.  This can mask the rollout look.  Second, the cores of the modern balls are so dynamic, that you still get some axis rotation even after the shell has burned all the rotational energy. 

Having said all of the above, over skidding ( not getting into a roll ) is very rare in the modern era.  If you throw a spinner, and/or have lots of ball speed, it can happen, but only on longer patterns.

Just an added note, the emergence of the pocket 7-10 split coincided with rollout accompanied by strong entry angle.  So it first on really short oil with polyester, then even on longer patterns with resin equipment