The Effect of the NFL Draft on College Teams

Alrighty, what we're talking about here is the seemingly logical and oft-cited idea that the more players a college team loses in the draft, the worse they'll do the next season. Phil Steele posted in March that from his analysis, "7 out of every 10 teams that rank among the top in the NCAA in players drafted struggle the next year and have a weaker record". On the surface it makes sense, but as you'll see it's not as simple as team - good players = more losses. Let's start at the beginning.

No, there's not a concrete direct correlation between number of draftees and how much a team falls the next year. If there was, they wouldn't need to play the games. But at the same time, it's pretty logical that the better a team performs, the more players it'll have drafted, the more talent they'll have to replace. So all of these things are related, but very loosely. Another thing that we have to take into account are all the players who graduate or end their college careers without being drafted. The average FBS team has 1.95 players drafted each year, but loses anywhere between 18-26 players annually due to graduation or used-up eligibility. So of the players that a team must replace, probably less than 10% of those are drafted. Does that mean the other 90% aren't any good? No, it just means they weren't in the upper echelon at their position. Here's some other things to know about the draft for context:

In any given year, draftees usually come from around 100 different schools, 80% of those being DI-A (FBS) schools, the other 20% being DI-AA, DII & DIII. But since the BCS began, only 28 teams have had at least one player drafted every year. The average number of players drafted per team per year comes out to about 1.95 for the FBS schools - for the non-FBS schools, the average is .18.

So now with that settled, let me explain my process a bit more. I'm only going back 11 years here, starting with 1999 NFL draft, mainly because it covers the whole BCS era and should help us zero in on more recent trends. The main stat I'm using is losses, not wins or winning percentage or any other "winning" measurement. But negative numbers signal more losses, so if you see -2, it means that a team had 2 more losses the following season, not that their total number of losses went down 2.

The first thing I set out to do was double-check Steele's 7 of 10 stat, not only because he doesn't provide any explanation of how he crunched the numbers but also because I like seeing the data for myself. Roughly, when he's talking about the teams that "rank among the top in the NCAA in players drafted", I'm going to take that to mean teams that had 6 or more players drafted in any given year. It's basically a Top 10, if you average it out.

Draftees 1999-2009
Year	# of team's with 6+ draftees	Teams
1999	12	8: Ohio St, Florida, Nebraska 7: Notre Dame 6: Georgia, Tennessee, Virginia, Texas A&M, Kansas St, North Carolina, Clemson, West Virginia
2000	8	9: Tennessee 7: Arkansas, Florida St, Michigan St 6: Ohio St, Texas A&M, Michigan, Arizona St, Florida
2001	9	9: Florida St 8: Miami (FL), Wisconsin 7: Nebraska 6: Ohio St, Kansas St, Georgia, Notre Dame, TCU
2002	12	11: Miami (FL) 10: Tennessee 8: Ohio St, Georgia, Florida, Virginia Tech 6: Kansas St, Notre Dame, North Carolina
2003	10	8: Miami (FL), Tennessee, Florida 7: Georgia, Notre Dame 6: Colorado, Michigan, Florida St, Texas A&M
2004	7	14: Ohio St 9: Miami (FL), Purdue 7: LSU 6: Nebraska, Pittsburgh, Arkansas
2005	7	11: Oklahoma 9: Florida St 7: Wisconsin, Virginia 6: Georgia, Stanford, Louisville
2006	11	11: USC 9: Miami (FL), Ohio St, Virginia Tech 8: Florida St 7: Georgia, LSU 6: Oklahoma, Texas
2007	6	9: Florida 8: Ohio St 7: Michigan, Texas, Notre Dame 6: Tennessee
2008	7	10: USC 8: Texas, Virginia Tech 7: LSU 6: Michigan, California, Arkansas
2009	9	11: USC 7: Ohio St, Oregon St, South Carolina 6: LSU, Georgia, Oregon, Cincinnati, Missouri

If we examine how each of these teams did the following season, here's what we get (along with the other categories of teams, just to be complete).

Losses the Following Season, 1998-2009 DI-A: by draftees
Draftees	# of team-seasons	More L's following	Same L's following	Fewer L's following	% more	% fewer	avg # of losses the following season
6+	98	65	12	21	66.3%	21.4%	-1.2
2-5	494	225	83	186	45.5%	37.7%	-0.3
1	290	120	45	125	41.4%	43.1%	0.0
0	404	135	67	202	33.4%	50.0%	0.5

It appears that this method pretty much confirms Steele's 7 of 10 assertion.

But as I said, that's not the whole story. I can go along with the 7 of 10 statistic, but there's a few caveats that we definitely have to add on.

The first is that even though there might be better than a 66% chance that a team with 6+ draft picks will lose more games next year, that number is made up of teams that have a penchant for staying on top. Of those 98 teams-seasons in the table above with 6 or more players drafted in a single year since 1999, there are 39 teams represented. Of those 39, 24 of them had at least one season where they had 6 or more players drafted but lost the same or fewer games the next season. (7 of those 24 had multiple season like that, including an amazing 4 such seasons from Ohio State.) So if your team is good enough to have 6+ players drafted, they're also probably good enough to overcome it.

And you've got to remember too, we're dealing with the cream of the crop here. That means that even if they technically have more losses the following season, it is most likely a drop from going 12-1 or 11-2 to 10-3 or 9-4. The vast majority (86%) of those 98 teams that lost 6+ draftees lost 6 games or less the following season, and the majority (56%) lost 4 games or less.

Overall, of the 117 DI-A teams that have had players drafted since 1999, 107 of them have had at least one year in which they did better (fewer losses) after having 2 or more players taken in the draft. Remember the average is 1.95 players per draft, so even after losing more talent than average, they still won more. (For clarification, just because 107 teams have done it doesn't mean it's really frequent - just that it's possible for any team. Adding up some of the above numbers, teams do better after losing 2+ draftees about 35% of the time.)

My second caveat to the 7 of 10 stat is this - there are a lot of other stats to look at that correlate better with the next season's losses than draftees does.

I looked at nearly 200 different seasonal variables, tracking their correlation with number of losses the following season. And as I said at the beginning, the correlations aren't significantly strong, but they're stronger with some stats than with others. I pared down the list due to a lot of overlap (for instance, if we're looking at # of TD's scored, we don't really need to look at # of extra points attempted as well). So here are the results of the relevant stats:

*blue = offensive stats, red = defensive stats, green = draft stats
*O/D Pairing refers to which stat's variable, offense or defense, has the higher correlation

Correlations with Losses the Following Season
Rank	Variable	Correlation	O/D Pairing
1	Losses	.462
2	Win%	-.447
3	Wins	-.427
4	avg Margin of Victory	-.330
5	Points per game	-.299	off
6	Points per Play	-.295	off
7	Points	-.292	off
8	TO+/-	-.287
9	avg spread +/-	.284
10	Total TD's	-.271	off
11	Yards per Pass	-.255	off
12	Spreads covered	-.245
13	Opp. Points per Play	.241	off
14	Opp. Points per game	.239	off
15	Yards per Play	-.231	off
16	Total Yards	-.231	off
17	Spread cover %	-.227
18	Opp. Total TD's	.224	off
19	Opp. Interceptions	-.221	def
20	Opp. Points	.219	off
21	Opp. Rushes	.213	def
22	Opp. Yards per Pass	.213	off
23	Rush TD's	-.212	off
24	Total First Downs	-.206	off
25	Opp. Rush-Net	.205	def
26	Opp. Rush-Gain	.202	def
27	drafted by position	-.201
28	draft multiplier	-.199
29	Opp. Rush TD's	.198	off
30	drafted by weight	-.193
31	# drafted	-.193
32	Spreads not covered	.193
33	Interceptions	.193	def
34	Opp. Yards per Play	.184	off
35	Opp. Total Yards	.178	off
36	Punts	.175	off
37	Punt Yards	.168	off
38	Opp. Pass Attempts	-.162*	def
39	Opp. Yards per Rush	.161	def
40	Rush-Net	-.152	def
41	Yards per Rush	-.150	def
42	Rush-Gain	-.145	def
43	Opp. Punts	-.142	off
44	Opp. Punt Yards	-.138*	off
45	Opp. Total First Downs	.132	off
46	Rushes	-.113	def
47	Fumbles Lost	.105	off
48	Fumbles	.084	off
49	Opp. Fumbles Lost	-.067	off
50	Penalty Yards	-.059*	off
51	Opp. Pass Completions	-.044	def
52	Opp. Penalty Yards	.043*	off
53	Opp. Fumbles	-.042	off
54	Pass Attempts	.035	def
55	Pass Completions	-.035	def
56	Penalties	-.030*	off
57	Opp. Penalties	.019*	off

Right off the bat you can see that there's a whole lot of variables that correlate with the next season's losses a lot better than # drafted. Losses, Wins, and Winning% are all above .4, right at the top, then there's a pretty big drop down to Avg. MoV, the only other variable above .3.

In addition to the simple # drafted, I've also added the variables of drafted by position, drafted by weight, and draft multiplier. (For drafted by position, I assigned each position a number of importance 10-1, based on their average draft spot. For drafted by weight, the #1 pick scored a 100, then on down exponentially to the low teens for the last players taken. For the multiplier, I just multiplied the position number and the weight number.) Interestingly, of those four variables, straight # drafted had the lowest correlation.

Even more interstingly, all of the top-ranked variables have the opposite correlation you might expect. For instance, since Points per game (-.299) is negative, that means the more points per game a team scored this year, the more losses they're likely to have next year. Or since Opp. Total TD's (.224) is positive, that means the more TD's a teams' opponents scored, the fewer losses they're likely to have next year. The only relevant stats that correlate the other way, (pass attempts, penalties, and penalty yards), have asterisks. So not too generally, the better you do this year, the worse you're likely to do next year. (But again, these correlations aren't too strong overall.)

Let's look at that most relevant correlation, between losses this year and losses next year, a bit more in depth. We know that it's hard to stay at the top season after season, and that's in part because the natural pull for all teams is .500. Here's the proof:

Losses the Following Season, 1998-2009 DI-A: by previous season losses
L's per season	# of team-seasons	More L's following	Same L's following	Fewer L's following	% more	% fewer	avg # of losses the following season
undefeated (0)	13	13	0	0	100%	0%	-3.2
1 loss	40	30	5	5	75.0%	12.5%	-2.0
2 losses	73	51	12	10	69.9%	13.7%	-1.7
3 losses	107	62	21	24	57.9%	22.4%	-1.3
4 losses	150	98	18	34	65.3%	22.7%	-0.9
5 losses	205	87	47	71	42.4%	34.6%	-0.2
6 losses	196	80	37	79	40.8%	40.3%	0.0
7 losses	170	48	33	90	28.2%	52.9%	0.5
8 losses	131	43	10	78	32.8%	59.5%	0.8
9 losses	104	24	14	66	23.1%	63.5%	1.2
10 losses	58	8	6	44	13.8%	75.9%	1.9
11 losses	32	1	5	26	3.1%	81.3%	2.8
12 losses	6	0	0	6	0%	100%	3.8
13 losses	1	0	0	1	0%	100%	4.0

1) The number of seasons when a team loses between 4-8 games are the majority (852 of 1,286, or 66%), and the seasons when a team loses 2 or fewer or more than 10 games are exceedingly rare (165 of 1,286, or 13%).
2) the fewer losses you have in a year the better your chances of having more losses the next season, and vice versa. (Meaning that in a 12-game season, if you lose 5 or fewer games, you're more likely to lose more than that the next season, and if you lose 7 or more games, you're more likely to lose fewer than that the next season.)
3) the number of losses you'll incur goes higher or lower as you get further away from 6, as seen in the last column.
4) all of this makes sense when you realize that a teams that wins 0 or 1 game(s) has little chance to do worse, and teams that win 12 or 13 games have little chance to do better - that's just pure probability.

So my point is that you can't really use number of players drafted as an accurate barometer of how well your team is going to do next season, but if you insist on some sort of measurement, just know that there are a lot of options that are better than that one.

(And if you're wondering, here's the table with teams, draft picks, each year, and whether or not they did better (blue) or worse (red) the following season.)

1998-2009 DI-A: draftees / # losses following season
Conf	Team	1999	2000	2001	2002	2003	2004	2005	2006	2007	2008	2009	total draftees	avg per year
Big10	Ohio St	8	6	6	8	5	14	3	9	8	3	7	77	7.0
ACC	Miami (FL)	3	5	8	11	8	9	5	9	5	3	1	67	6.1
Pac10	USC	5	5	3	2	5	4	5	11	5	10	11	66	6.0
SEC	Georgia	6	3	6	8	7	4	6	7	4	4	6	61	5.5
SEC	Tennessee	6	9	5	10	8	4	3	5	6	3	1	60	5.5
ACC	Florida St	4	7	9	2	6	5	9	8	5	3	1	59	5.4
SEC	Florida	8	5	4	8	8	5	3	3	9	2	3	58	5.3
SEC	LSU	3	2	3	5	4	7	4	7	5	7	6	53	4.8
Big10	Michigan	4	6	5	4	6	4	3	4	7	6	2	51	4.6
Big12	Texas	3	4	4	2	4	5	3	6	7	8	4	50	4.5
Big12	Nebraska	8	3	7	4	4	6	4	4	4	3	3	50	4.5
Big10	Wisconsin	4	4	8	4	4	3	7	5	2	4	4	49	4.5
ACC	Virginia Tech	2	5	3	8	2	5	3	9	3	8	1	49	4.5
Indy	Notre Dame	7	1	6	6	7	5	2	3	7	4	1	49	4.5
Big12	Oklahoma	3	2	2	2	4	3	11	6	3	4	5	45	4.1
Big10	Penn St	2	4	4	2	6	4	0	6	5	2	5	40	3.6
Pac10	California	5	4	2	2	4	2	5	3	4	6	3	40	3.6
SEC	Alabama	2	4	4	4	5	4	4	5	3	0	4	39	3.5
ACC	Virginia	6	4	1	3	2	1	7	5	2	3	4	38	3.5
Big12	Texas A&M	6	6	5	2	6	1	3	2	0	5	2	38	3.5
SEC	Auburn	2	4	3	3	0	4	5	4	5	5	3	38	3.5
Pac10	Oregon	3	2	1	6	3	4	2	4	3	3	6	37	3.4
Big12	Kansas St	6	5	6	6	4	2	1	1	3	2	1	37	3.4
SEC	Arkansas	5	7	2	1	1	6	2	1	4	6	1	36	3.3
Pac10	Arizona St	2	6	4	4	3	2	3	2	2	5	2	35	3.2
Big10	Purdue	2	2	5	2	1	9	1	4	3	3	2	34	3.1
Big10	Iowa	2	2	1	3	5	5	4	2	3	3	4	34	3.1
Big10	Michigan St	2	7	3	5	1	2	4	2	3	3	1	33	3.0
ACC	North Carolina	6	1	4	6	1	3	3	1	0	2	5	32	2.9
Pac10	Oregon St	3	0	4	1	3	4	3	2	2	2	7	31	2.8
Pac10	Stanford	0	2	2	6	4	3	6	4	3	0	0	30	2.7
ACC	Clemson	6	0	3	0	2	2	3	3	5	2	4	30	2.7
ACC	NC State	2	2	2	2	2	3	3	6	3	2	2	29	2.6
Big12	Colorado	3	4	0	5	6	2	0	4	2	2	1	29	2.6
BigEast	Louisville	0	2	1	1	4	0	6	4	4	5	2	29	2.6
SEC	South Carolina	0	2	0	5	3	3	3	2	2	1	7	28	2.5
Pac10	UCLA	3	1	1	6	2	4	4	3	1	3	0	28	2.5
ACC	Maryland	2	2	2	3	1	5	2	3	2	1	5	28	2.5
BigEast	Pittsburgh	0	1	1	3	3	6	1	2	3	3	4	27	2.5
BigEast	Syracuse	3	2	4	2	2	3	1	4	2	0	2	25	2.3
ACC	Boston College	3	3	1	2	3	2	0	3	2	3	2	24	2.2
ACC	Georgia Tech	3	3	0	2	0	4	0	3	2	3	4	24	2.2
Pac10	Arizona	4	5	1	0	3	0	0	1	4	4	2	24	2.2
MtnWest	Brigham Young	3	3	2	5	2	1	3	1	1	1	2	24	2.2
MtnWest	Utah	1	3	2	2	3	0	5	2	2	0	4	24	2.2
BigEast	West Virginia	6	4	0	0	2	1	3	1	0	3	3	23	2.1
MtnWest	TCU	0	0	6	1	2	1	1	3	2	0	5	21	1.9
Big12	Texas Tech	2	2	1	1	2	2	3	1	3	0	4	21	1.9
SEC	Mississippi	0	3	3	1	1	4	3	0	2	0	4	21	1.9
Pac10	Washington	2	2	5	3	0	4	2	1	2	0	0	21	1.9
SEC	Mississippi St	4	4	4	1	3	0	2	2	1	0	0	21	1.9
BigEast	Cincinnati	1	0	1	1	3	0	4	0	2	2	6	20	1.8
WAC	Hawaii	0	3	1	1	3	2	1	0	5	1	3	20	1.8
Big10	Illinois	1	2	2	1	5	2	2	0	1	1	3	20	1.8
CUSA	Southern Miss	1	4	4	2	1	3	2	0	0	1	2	20	1.8
WAC	Fresno St	1	0	1	4	1	1	2	3	4	1	2	20	1.8
Big12	Missouri	1	1	1	0	2	0	3	2	1	2	6	19	1.7
MtnWest	San Diego St	0	3	0	3	1	1	3	2	0	5	1	19	1.7
Big10	Minnesota	0	2	4	3	1	1	1	4	1	1	0	18	1.6
ACC	Wake Forest	1	3	0	0	3	0	1	1	2	3	4	18	1.6
Big10	Northwestern	3	1	2	3	1	0	3	3	0	0	0	16	1.5
MtnWest	Colorado St	4	2	2	0	0	3	1	1	1	0	1	15	1.4
SEC	Kentucky	2	1	2	1	2	1	1	0	0	4	1	15	1.4
CUSA	UCF	2	1	0	1	4	1	0	1	1	3	1	15	1.4
Pac10	Washington St	1	1	1	2	2	1	3	1	1	1	1	15	1.4
BigEast	Rutgers	0	0	1	0	1	2	0	0	3	2	5	14	1.3
Big12	Oklahoma St	0	2	0	0	1	3	3	1	2	0	1	13	1.2
SEC	Vanderbilt	1	0	4	0	1	0	2	1	0	3	1	13	1.2
MtnWest	UNLV	1	1	0	4	0	1	2	0	1	1	1	12	1.1
WAC	Boise St	0	1	1	2	1	0	0	1	4	2	0	12	1.1
MtnWest	New Mexico	0	2	1	1	0	0	2	2	1	1	2	12	1.1
CUSA	Marshall	0	4	1	1	3	1	1	0	1	0	0	12	1.1
CUSA	Memphis	1	0	3	0	2	1	0	2	1	0	1	11	1.0
WAC	San Jose St	2	0	1	0	1	1	0	0	2	1	3	11	1.0
BigEast	Connecticut	0	0	0	0	0	0	2	0	1	2	4	9	1.0
BigEast	South Florida	0	0	0	0	3	1	0	0	1	2	1	8	1.0
Big12	Iowa St	0	0	3	1	1	0	1	1	1	2	0	10	0.9
MAC	Miami (OH)	2	2	0	0	0	2	1	1	1	0	1	10	0.9
CUSA	Tulane	1	1	1	1	0	2	1	0	0	1	1	9	0.8
Big12	Kansas	0	0	1	2	0	1	1	0	0	4	0	9	0.8
Big12	Baylor	2	0	1	0	1	0	1	1	2	0	1	9	0.8
CUSA	East Carolina	2	0	0	2	0	1	0	1	1	1	1	9	0.8
SunBelt	Troy	0	0	0	0	2	0	1	0	1	1	1	6	0.8
WAC	Louisiana Tech	1	2	0	1	0	2	0	0	1	0	0	7	0.6
CUSA	Houston	0	1	0	0	1	1	1	0	1	1	1	7	0.6
MAC	Northern Illinois	0	0	2	1	0	1	0	0	2	0	1	7	0.6
Big10	Indiana	0	0	0	1	1	0	1	2	0	2	0	7	0.6
CUSA	UTEP	0	0	1	1	0	0	1	1	2	0	0	6	0.5
MAC	Akron	0	0	1	1	0	0	1	1	1	1	0	6	0.5
WAC	Idaho	0	1	2	0	0	1	0	0	0	1	1	6	0.5
MAC	Toledo	0	0	0	1	1	0	1	1	0	2	0	6	0.5
MAC	Temple	0	0	1	1	2	0	1	0	0	0	1	6	0.5
SunBelt	Florida Intl	0	0	0	0	0	0	0	0	2	0	0	2	0.5
MAC	Ball St	0	0	0	0	0	0	3	0	0	0	2	5	0.5
CUSA	SMU	2	0	0	0	1	0	0	0	1	0	1	5	0.5
MAC	Kent St	1	1	0	0	0	0	0	0	1	1	1	5	0.5
CUSA	Tulsa	0	1	0	1	0	0	1	1	0	1	0	5	0.5
MAC	Central Michigan	0	0	0	0	0	0	2	0	3	0	0	5	0.5
SunBelt	LA-Lafayette	1	0	0	1	2	0	1	0	0	0	0	5	0.5
WAC	Nevada	0	0	0	0	0	2	0	1	1	0	1	5	0.5
WAC	Utah St	1	0	0	0	1	1	0	0	0	2	0	5	0.5
MAC	Western Michigan	0	0	0	0	0	1	0	2	0	0	2	5	0.5
MAC	Eastern Michigan	1	0	0	0	1	0	1	0	0	1	1	5	0.5
CUSA	Rice	0	0	0	0	2	0	0	0	0	0	2	4	0.4
MAC	Bowling Green	0	0	0	0	0	1	1	1	0	1	0	4	0.4
MtnWest	Wyoming	0	0	1	0	0	1	0	1	1	0	0	4	0.4
SunBelt	Arkansas St	0	0	0	0	0	1	0	0	1	1	1	4	0.4
CUSA	UAB	0	0	1	2	0	0	1	0	0	0	0	4	0.4
SunBelt	Mid Tenn St	0	0	0	1	1	0	0	0	0	1	0	3	0.3
MAC	Buffalo	0	1	0	0	0	0	0	0	0	2	0	3	0.3
SunBelt	LA-Monroe	0	1	0	0	0	0	1	0	1	0	0	3	0.3
MAC	Ohio	0	0	0	1	0	0	0	0	0	1	1	3	0.3
ACC	Duke	1	1	0	0	0	1	0	0	0	0	0	3	0.3
SunBelt	New Mexico St	0	0	1	0	1	0	0	0	0	0	0	2	0.2
WAC	Air Force	1	0	0	0	0	0	0	0	0	0	0	1	0.1
Indy	Army	0	0	0	0	0	0	0	0	0	1	0	1	0.1
SunBelt	North Texas	0	0	0	0	0	1	0	0	0	0	0	1	0.1