Where do you stand on the Deep Threats Need a Good Left Tackle idea?

It seems to be good conventional wisdom, but I haven’t thought about it more than that. I assume the theory is that a QB is only going to be able to take advantage of the deep threat if his LT his giving him an extra second or two for the WR to get downfield and the QB to find him.

But this seems like one of those things that is very difficult to measure:
– does the WR play well because the LT is good – or does the LT look good because they have a good WR?
– How helpful is yards/reception? If Wallace catches an 8-yard pass and then runs for 40 more, I don’t think that was because the LT was good. But maybe yards/reception and YAC kind of averages out over time?
– How often do teams really throw deep balls, anyway? 15% of the time? And then how many of those are going to the main deep threat? Seems like we’re really getting into tiny sample sizes.

Wouldn’t be too hard, but ultimately, the sample size is too small. I didn’t have the time to do an exhaustive study, but I should revisit the issue and then use N+2 numbers.

Do you have any other ideas on how to measure this? Where do you stand on the Deep Threats Need a Good Left Tackle idea?