NFL Scoring Differentials Tell an Odd Story about the Vaunted “Half-time Adjustment”

Half-time adjustments in the NFL. The coaching staff huddle in a side office looking at black-and-white still-photos of first half plays. Wry observations are made, leading to a flash of inspiration. The coaches rush into the locker room, and a hush descends. The players await instruction…and inspiration. Like Moses, the head-coach lays out the new game plan, how we will attack, how the other team won’t see it coming, how WE WILL WIN.  With a few more inspirational words, the coaches lead the team out of the locker room, back on to the field, onward towards victory.

There are some problems with this popular image. One problem is that locker rooms at half-time are chaotic places, with players changing equipment, getting medical care, refueling, vomiting, etc. Players can’t really take-in much new information in this situation. And coaches have very little time to gather, let alone process, new information about what the other team is doing. If they had a whole week to prepare for what they would see in the first half, they now have about 20 minutes to make on-the-fly adjustments for the second half.

So are “half-time adjustments” even a real thing?

Clearly some teams play better in the second half than in the first half. But given that the very premise of half-time adjustments by the coaching staff deserves some skepticism, we should consider other reasons why some teams do better in the second half than they do in the first. Just one example –  a slow but highly physical team might struggle to break big plays in the first half, but could so fatigue the other team that they create more scoring chances in the second half. There could be lots of other reasons too. But let’s just look at the data first.

Here are the touchdown and field-goal scoring differentials for each team this season, broken down by half. The last column shows the improvement (or decline) in their scoring differential in the second half.

NFL scoring differential by half

Let’s start with the easy observations: teams like Denver and Seattle show very little difference between their first and second half scoring differentials because they dominate other teams in both halves of play. Jacksonville and Minnesota have a small differential as well, because they tend to lose both halves of every football game.

If you wanted to argue that on-the-fly half-time adjustments are meaningful, you might note that teams coached by certified geniuses like Bill Belichick and Sean Payton are in the top 10. But they lag behind Indianapolis, Pittsburgh and Arizona, teams with coaches who are less often referred to as geniuses. And last year’s newest candidate for genius status – Jim Harbaugh – is in the bottom five on this list.

Also note that a couple of coaches on the hot-seat, like Mike Shanahan and Rex Ryan, actually look pretty good by this measure.

This set of observations is still half-baked, and is probably worth revisiting later.

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