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NFL Kickoff rule changes: Impact on offense

Posted by Chase Stuart on March 23, 2011

Yesterday, 26 of the league's 32 owners voted to change the NFL's kickoff rules, moving the placement of the ball from the 30- to the 35-yard line.

[Leon] Washington and others around the league said the change, made to address player-safety issues, would breed more touchbacks and substantially impact field position, likely leading to less scoring.

"There just won't be as many returns, and I think it's going to affect things like scoring, and there'll be more of an emphasis on directional kicking ...," Cincinnati Bengals special-teams coach Darrin Simmons told his team's official website. "There are going to be more touchbacks and more 80-yard drives, and scoring drops sharply because there are a lot more scoring drives of 70 yards than drives over 80."

Touchbacks will continue to be brought out to the 20, and teams still will be allowed to use the two-man blocking wedge.

Fan reaction has been mostly negative. Cries about player safety from fans discussing an 18-game schedule have turned into cries about "ruining the game" when it comes to minimizing special teams. In reality, most of these complaints are due to a general resistance to change, with whatever the flavor du jour serving as a comfortable red herring.

But what about the claim that this will decrease scoring? Nate Dunleavy agrees:

A league-wide reduction in offense. Because even the worst special teams units generally start on the good side of the 20 after kickoffs (I believe Indy started around the 22), an increase in touchbacks will move average starting field position backwards for all NFL teams. Teams with good return games will be hurt more than teams with bad return games, but all teams should see their average starting field position go backwards, even Indy. There is a very strong relationship between starting field position and the points a team can expect to score. The cumulative effect of dozens of extra touchbacks will be a reduction in scoring. As noted, the Colts should feel this pinch far less than most teams, as it will likely affect their starting field position after kickoffs by less than a yard or so.

I'm not so sure I agree with Nate; while teams receiving a kickoff may be less likely to score, by definition, teams kicking off will be more likely to score next. In reality, this rule change is sure to have little actual impact on scoring, but that doesn't mean we can't engage in a quick thought exercise. Let's take this rule change to the extreme: suppose instead of teams kicking off from the 30-yard line, from now on the opposing team gets possession of the ball at their own 7-yard line. How would that impact play?

At the start of every half, and following every touchdown and field goal, instead of getting a chance to receive and return a kickoff, a team is placed in the shadow of their own goal-posts. How would this impact scoring? It's obvious that it would make scoring more difficult for the "receiving" team. However, it would make scoring less difficult for the "kicking" team. How do those elements balance out?

We assume that following a kickoff, a team will start its drive at, on average, the 27-yard line. According to David Romer, that is worth 0.7 points to the offensive team. Having the ball at your own 7-yard line is worth 0.6 points to the defensive team. In that case, the team on offense is less likely to score than its opponent. For the offense, this hypothetical rule change would cost it 1.3 points following each kickoff compared to where things stand today.

Now, scoring a touchdown is worth 6.3 points, on average. Under this scenario, a touchdown is worth 7.6 points. Considering that last season there were 9.6 kickoffs per game, this would be a serious change to the way the game is played. However, does that *necessarily* mean less scoring? Couldn't it mean even more scoring? Or would it be a zero-sum game, where if one team scores less the other scores more?

For the most part -- including from the 7-yard line to the 27-yard line, field position values are linear. The table below lists the approximate value of having possession of the ball on 1st down at each yard line:

Yd	Val	To Go
1      -1.55	99
2      -1.35	98
3      -1.15	97
4      -1.00	96
5      -0.85	95
6      -0.70	94
7      -0.60	93
8      -0.50	92
9      -0.40	91
10     -0.35	90
11     -0.28	89
12     -0.21	88
13     -0.14	87
14     -0.07	86
15	0.00	85
16	0.05	84
17	0.10	83
18	0.15	82
19	0.20	81
20	0.25	80
21	0.32	79
22	0.38	78
23	0.45	77
24	0.51	76
25	0.58	75
26	0.64	74
27	0.71	73
28	0.77	72
29	0.84	71
30	0.90	70
31	0.96	69
32	1.03	68
33	1.09	67
34	1.15	66
35	1.22	65
36	1.28	64
37	1.35	63
38	1.41	62
39	1.47	61
40	1.54	60
41	1.60	59
42	1.64	58
43	1.69	57
44	1.73	56
45	1.78	55
46	1.82	54
47	1.87	53
48	1.91	52
49	1.96	51
50	2.00	50
51	2.04	49
52	2.09	48
53	2.13	47
54	2.18	46
55	2.22	45
56	2.27	44
57	2.31	43
58	2.36	42
59	2.40	41
60	2.46	40
61	2.53	39
62	2.59	38
63	2.65	37
64	2.72	36
65	2.78	35
66	2.85	34
67	2.91	33
68	2.97	32
69	3.04	31
70	3.10	30
71	3.17	29
72	3.23	28
73	3.30	27
74	3.36	26
75	3.43	25
76	3.49	24
77	3.56	23
78	3.62	22
79	3.69	21
80	3.75	20
81	3.80	19
82	3.85	18
83	3.90	17
84	3.95	16
85	4.00	15
86	4.07	14
87	4.14	13
88	4.21	12
89	4.28	11
90	4.35	10
91	4.40	 9
92	4.50	 8
93	4.60	 7
94	4.70	 6
95	4.85	 5
96	5.00	 4
97	5.15	 3
98	5.35	 2
99	5.55	 1

As you can see, going from the 7- to the 27-yard line is worth 1.31 points to the offense, or 0.66 points per 10 yards. Going from the 27- to the 47-yard line is worth 1.16 points, or 0.58 PP10Y. How about from the 27 to your opponents' 27? That's 2.59 points, or 0.56 PP10Y. Going from the 7 to the 7 is worth 0.60 PP10Y.

Assume three incomplete passes. Instead of having the ball at the 7-yard line -- which is worth -0.6 points to the offense -- they punt and the opponent takes over at the 47, which is worth -2.1 points to the punting team. If they had the ball at the 27-yard line -- worth 1.3 points to the offense -- following a three-and-out and a 40-yard punt, the opposing team would get the ball at their own 33-yard line, which is worth -1.1 points to the punting team.

What's that all mean? Following a standard drive that gains zero yards, a team loses 1.5 points to the opposing team. Following a standard drive that gains zero yards under this hypothetical rule environment, a team loses.... 1.4 points to the opposing team. It's a slightly less painful transition because it's exponentially harder to score from inside one's own ten yard line, where it's only slightly more difficult to score from your 33-yard line than your opponent's 47-yard line.

But what about a *good* drive? A 50-yard bomb from your own 7 takes you to your opponent's 43-yard line, a value of 2.3 points and a net improvement of 2.9 points. A 50-yard completion from your 27-yard line is an improvement of ... 2.85 points. Again, we are not discussing significant improvements.

And that's *with* a huge change in starting field position, from your own 27 (on average) to your own 7. The actual change will certainly result in a few more touchbacks, but I suspect average starting field position following a kickoff will be around the 23-yard line now, instead of the 27. And that will have a negligible impact on the game.

But the points above just discuss the value of having the ball: what about gross scoring? If we moved the starting spot from the 27 to the 7, do games that used to be 27-21 now just finish at 20-13? On some level, scoring has to go down, because we're outlawing kick returns. Kick returns are among the most random plays in a game, and eliminating 9.6 opportunities for a kickoff score or a fumble will slightly depress scoring. Kick returns don't take much time (the clock stops after every one) but can be very high leverage plays. And the great shootouts will probably be deflated. On those days where neither team is playing defense, requiring each team to drive 93 yards instead of 73 yards will just bleed more clock and result in fewer possessions (and scores) for each team. Outside of those events, though, I'm not sure why scoring will go down. Yes, on the margins we might see a decrease, but the kickoff team will now, on average, get its next possession in better field position. For the most part, I think such a rule change would be a wash on net scoring, and this actual rule change is sure to have little impact.

But the biggest issue with the hypothetical rule change would come stylistically. Right now, each possession resembles each possession in tennis or chess or baseball. After my turn to serve or move or bat, it's your turn. After I score a touchdown, you are now in a more favorable position to score. After I served, or moved my knight, or had six players up at bat, you are now in a more favorable position to gain an edge. But if we change the value of receiving a "kickoff" from +0.7 to -0.6, the sport switches and begins to resemble billiards or backyard basketball played under "Winner's Out" rules.

Perhaps counter-intuitively, going from "Winner's Out" to "Loser's Out" doesn't change your probability of winning a game, regardless of the skill level difference between you and your opponent. But by that same token, "Winner's Out" rules -- where following a score, the scoring player or team regains possession -- lead to streaky behavior.

If the NFL actually instituted the "7-yard line" rule, we would see many more historic comebacks. For now, the Bills' 32-point comeback over the Oilers in the 1992 playoffs remains the largest comeback in league history. But a "Winner's Out" response to scoring would make it easier to both (a) grab a large lead early and (b) come back from a large lead late. If after every touchdown the opposing team got the ball at the 7, this wouldn't be an incredibly rare start to a game:

Drive 1: Team A touchdown
Drive 2: Team B three and out; punts.
Drive 3: Team A takes possession of ball at 50. Touchdown.
Drive 4: Team B three and out; punts.
Drive 5: Team A takes possession of ball at 50. Touchdown.

Just like that, and it's 21-0. Of course, it your team is trailing by 35 points in the second half, you still have hope. The key takeaway, in my opinion, is not that moving the kickoff from the 30- to the 35-yard line will decrease scoring, but rather that it will (imperceptibly, of course) increase big comebacks. Kicking teams will be further incentivized to try onsides kicks, as the receiving team will be five yards further away from the kicking team's end zone in the event of an unsuccessful kick. More onside kicks and the ability to pin the receiving team deep will lead to larger comebacks. And it will simply lead to streakier behavior by both teams, in general.

Of course, this is just on a league-wide basis. The much larger impacts will come on the team level, where the Browns, Bears, Seahawks and Jets will be hurt. Chargers fans, rejoice: we're one step closing to removing special teams entirely.

This entry was posted on Wednesday, March 23rd, 2011 at 3:12 pm and is filed under Rule Change Proposals. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.