I guess it doesn't matter HOW you compare/test an aspect of technique, so long as you do it the same way. Cochran and Stobbs themselves pointed out that the correct basic golf swing is a lead arm swing. The line-up of the shaft to a line from the left shoulder to the hands, when both are vertical, is exhibited by virtually all great male ball-strikers. There must be a good reason why. I heard just the other day that Bobby Jones' swing was tested to have the same timing as if gravity-powered. I would like to find out more about that, but in reference to the line-up, this is surely true.
hmm - I've heard that claim about Jones and his gravity-powered swing pretty heavily criticised. Since I read the original claim in a Jim Flick book that otherwise studiously avoided anything approaching physics or mechanics, I've not really given it much more thought since then.
The issue of the line-up still seems to me like a question of degree. I feel like you could argue that there's as great a difference between Trevino/Hogan and "PGA average" as there is between "PGA Average" and "LPGA Average". Either way, my point is that where you draw the line for the upper lever is arbitrary. The lead arm only swing is a simplification. Once you add a trailing hand to the club, you surely change the forces and paths. So why not reflect this when you interpret the location of the upper lever?
I agree that for comparison purposes this should at least be done consistently - but if you draw it up the left arm, then flipping suddenly looks like a major issue. Draw it to the sternum - and it doesn't.
Flipping used to be what we all worried about. Now it's handle-dragging. Maybe the guys who line it up later are more interested in controlling their trajectory.