Parlaying O/U and ATS in NCAAF Relative to One Another

After my recent post on parlaying O/U and ATS depending upon the size of the spread, I received a request to look at the ratio of spreads and totals in NCAAF. So situations in which the spread is an outlandish percentage of the total, like 35%+. For example, in today's Georgia-Vanderbilt game, Georgia is favored by 25.5 with an over/under of 56. That 25.5 point spread thus represents 45.5% of the overall expected points in the game (25.5/56), which is a fairly lopsided ratio. Is there value in games where one team's score alone is supposed to make up a good portion of that game's total points?

As before, a standard 2-team payout is 13/5 (+260), and at +260, you need to hit above 27.78% of the time to turn a profit. (Note: with heavily skewed NCAAF games, most books actually don't let you parlay a side and an over/under. But this strategy can be applied to individual bets as well). So I looked at varying ratios of spreads to totals over the past 5 years of college football, and combining bets on the favorite and the over is a remarkably profitable strategy as the ratio escalates:

Ratio of Spread to Total
FAV + OVER	Actual	%	Return	ROI	% Occur
20%	414	27.62%	-9	-0.57%	42.18%
25%	339	28.70%	39	3.34%	33.23%
30%	273	30.67%	93	10.43%	25.04%
35%	215	32.33%	109	16.39%	18.71%
40%	158	32.71%	86	17.76%	13.59%
45%	114	34.03%	75	22.51%	9.43%
50%	76	33.78%	49	21.60%	6.33%
55%	58	37.66%	55	35.58%	4.33%
60%	41	37.27%	38	34.18%	3.10%
65%	24	37.50%	22	35.00%	1.80%

The more outlandish the ratio is, the more profitable it is, but of course the higher that ratio gets, the less often it occurs. If you can get any favorite that makes up 30%+ of the overall total, you're looking at a very high ROI.

I also looked at dogs + unders, in case you want to cover your risk a bit and hedge on the other extreme. There is some value in doing so, but only once you get to the sweet spot of a 45-60% ratio:

Ratio of Spread to Total
DOG + UNDER	Actual	%	Return	ROI	% Occur
20%	403	26.88%	-48	-3.22%	42.18%
25%	320	27.10%	-29	-2.46%	33.23%
30%	230	25.84%	-62	-6.97%	25.04%
35%	178	26.77%	-24	-3.64%	18.71%
40%	134	27.74%	-1	-0.12%	13.59%
45%	100	29.85%	25	7.46%	9.43%
50%	71	31.56%	31	13.60%	6.33%
55%	49	31.82%	22	14.55%	4.33%
60%	35	31.82%	16	14.55%	3.10%
65%	17	26.56%	-3	-4.38%	1.80%

Parlaying O/U and ATS

Every sporting event with a spread and an over/under has four possible combinations of outcomes, disregarding a push:

• FAV + OVER
• FAV + UNDER
• DOG + UNDER
• DOG + OVER

Most books let you parlay these combinations together on the same event, for the standard 2-team payout of 13/5 (+260). So is there any value to doing so? In theory, each combination should occur ~25% of the time. At +260, you need to hit above 27.78% to turn a profit (parlays are very rarely an efficient bet compared to individual ones).

I looked at the last 5 seasons for NBA, NFL, and NCAAF (NCAAB data can be spotty, especially for O/U) to see if any trends stood out. Over that many games nothing hurdles above 27.78%:

NBA	Actual	%	Exp	Dif
FAV + OVER	1,515	23.94%	1,582	-66.75
FAV + UNDER	1,638	25.89%	1,582	56.25
DOG + UNDER	1,561	24.67%	1,582	-20.75
DOG + OVER	1,613	25.49%	1,582	31.25
Total	6,327	100.00%
NFL	Actual	%	Exp	Dif
FAV + OVER	282	24.02%	294	-11.5
FAV + UNDER	289	24.62%	294	-4.5
DOG + UNDER	304	25.89%	294	10.5
DOG + OVER	299	25.47%	294	5.5
Total	1,174	100.00%
NCAAF	Actual	%	Exp	Dif
FAV + OVER	917	25.80%	889	28.5
FAV + UNDER	857	24.11%	889	-31.5
DOG + UNDER	920	25.89%	889	31.5
DOG + OVER	860	24.20%	889	-28.5
Total	3,554	100.00%

What about at the extremes, when one team is favored by a lot? Some small trends did stand out on larger spreads, albeit at smaller sample sizes of course.

NBA really doesn't do much. 7% of games matched the criteria of a spread >= 12, and there's not much of a return to be had:

NBA, ATS >= 12	Actual	%	Return	ROI
FAV + OVER	80	18.02%	-156	-35.14%
FAV + UNDER	124	27.93%	2	0.54%
DOG + UNDER	129	29.05%	20	4.59%
DOG + OVER	111	25.00%	-44	-10.00%
Total	444	100.00%

NFL does it a bit better. 12% of games had spreads >= 10, and there's some nice value in combining the underdog and the under:

NFL, ATS >= 10	Actual	%	Return	ROI
FAV + OVER	41	28.08%	2	1.10%
FAV + UNDER	30	20.55%	-38	-26.03%
DOG + UNDER	45	30.82%	16	10.96%
DOG + OVER	30	20.55%	-38	-26.03%
Total	146	100.00%

In the end, NCAAF has the largest opportunity, with 18% of games having spreads >= 20.5 and some really nice value pairing the favorite and the over:

NCAAF, ATS >= 20.5	Actual	%	Return	ROI
FAV + OVER	204	31.83%	93	14.57%
FAV + UNDER	129	20.12%	-177	-27.55%
DOG + UNDER	164	25.59%	-51	-7.89%
DOG + OVER	144	22.46%	-123	-19.13%
Total	641	100.00%

Fading State in NCAAF/NCAAB

Awhile back during college football season, some friends of mine observed the fact that NC State seems to consistently blow it in football and basketball and seemingly "underpeforms". (Also note that I wrote about this overall trend in the ACC of "Clemsoning".) We have a saying to explain this behavior: "State = State", which illustrates how the circular universe of NC State athletics seems to collapse upon itself year-after-year under the weight of unfounded expectations.

One way to gauge this is to see if "fading" (i.e. betting against) State against the spread would be a profitable exercise. I used Prediction Machine's Trend Machine to pull NC State's games against Division 1 opponents (non-FCS) in both college football and basketball over the past 5 years. They have amassed the following records against the spread (ATS) in each sport:

Football: 25-32, 43.86%
Basketball: 87-69, 55.77%

The breakeven win percentage needed to make money ATS is 52.38%, so fading State in football would actually be profitable. However, they have posted a rather robust 55.77% win rate ATS in basketball in recent years. So it looks like only football is applicable in this "fading State" strategy.

Profiting off of Clemsoning

Originally posted Tuesday, November 3, 2015 at probabilis.blogspot.com

In recent years, the term "Clemsoning" has become synonymous with a team shockingly losing a game in which they were large favorites. While the origins of attributing the phrase to Clemson aren't concrete, Clemson has experienced more than its fair share of mind boggling losses, and it may have started with their 2 TD loss to Georgia Tech in 2011.

Related: West Virginia just scored again!

But this is the ACC! There's wealth to be spread! This is the conference that gave us this:

And this:

And this:

That last game (NC State over Florida St.) is an example of Clemsoning, and is one of the inspirations for this post: NC State was a 7/1 underdog in that game. With the ACC's consistently maddening mediocrity and tendencies for upsets, could you profit off of ACC teams "Clemsoning" in conference play?

Thanks to Prediction Machine's Trend Machine, I was able to easily pull all ACC conference games since 2011 (the year "Clemsoning" appears to have started) and look at how often the underdog won, and what the payoff would've been had you bet on that team. If you had simply bet underdogs against the spread, you would've won 52% of the time, which would've been a losing strategy (you need to win 52.38% of spread bets to break even). But we don't care about that! We want straight up victories, the kind that lead to celebrations like this!

The underdog won the game outright 29.13% of the time, which is quite a bit more than the average of around 20.43% (see: "Line (updated)"). Had you blindly bet the underdog in each game, you would've returned a profit of +910 units, which equates to a 3.96% ROI over the past 4 years. So not that much. However, the emotional return is priceless: