Predicting Big Games Using NBA Vegas Lines

by Ethan Haskell (Ethan) Last Updated 2015-01-09 16:47:26

Vegas Lines are one of many ways to help predict daily fantasy value, but the interpretations of spreads and Over/Unders can be a challenge. The proof is always in the numbers though so we went back and looked at all of the Vegas odds for the month of January and found which games lead to the most fantasy explosions, similar to how RG Blogger Hambazaza did in his Odds and Ends series. The sample size isn’t huge, but 240 total games should be enough to give us a pretty good idea of how the Vegas Odds and big fantasy nights correlate.

Games included are from January 1st to February 1st

Basically, the data below shows different categories of over/unders, spreads and over/unders + spreads along with how many games played in the last month match that split. Then it shows how many total players in those games scored more than 40 fantasy points and more than 50 fantasy points, along with how many there were per each game played.

LEGEND

GP – Games Played for given range
40+ FP – Number of individual performances of 40 fantasy points or greater in given range
40+/GP – 40+ FP Games divided by Games Played
50+ FP – Number of individual performances of 50 fantasy points or greater in given range
50+/GP – 50+ FP Games divided by Games Played

Over/Unders

We’ll start with the easiest number to interpret, the O/U. It’s broken down into 7 ranges for each split where it’s discussed in the article:

For the 240 games between 1/1/14 and 2/1/14, here’s what we saw:

OVER/UNDERS	GP	40+ FP	40+/GP	50+ FP	50+/GP	FPPG
0 to 190 Pts	31	43	1.39	13	0.42	364.56
190 to 195 Pts	31	35	1.13	11	0.35	371.24
195 to 200 Pts	50	73	1.46	21	0.42	383.40
200 to 205 Pts	52	74	1.42	14	0.27	383.50
205 to 210 Pts	36	73	2.03	18	0.50	401.96
210 to 215 Pts	26	45	1.73	14	0.54	381.94
215+ Pts	14	23	1.64	11	0.79	421.42

There were an average of more than 2 40+ fantasy point scorers in games played with an over/under between 205 and 210 points, which was the most among all categories.
For producing 50+ point games, the highest Over/Under total won out with .79 50+ performances per game played with an O/U greater than 215.
The sample size for games with O/Us between 195-200 and 200-205 are pretty large (50 games each), but there’s a huge drop off in 50+ fantasy performances from the 195-200 to the 200-205 range, with .15 less per game in the higher over/under range.

Spreads

Games here include all spreads, and aren’t broken down by individual team (favored or underdog). So if the absolute value of the spread falls in the ranges below, it was used to count this data. Further down, we’ll look at how being favored or being an underdog impacts big nights for fantasy.

SPREADS	GP	40+ FP	40+/GP	50+ FP	50+/GP	FPPG
0-3 Pts	58	93	1.60	30	0.52	386.70
3-6 Pts	78	122	1.56	33	0.42	382.23
6-9 Pts	54	82	1.52	19	0.35	381.30
9-12 Pts	39	54	1.38	14	0.36	384.74
12+ Pts	11	15	1.36	6	0.55	398.65

Sample size is the most likely reason why games with 12+ point spreads have the highest rate of 50+ fantasy game performances, yet rank last in 40+ fantasy point games.
It’s pretty evident here that close games are one of the best indicators of finding big fantasy games, as the number of 40+ fantasy point performances per game played slowly drops as the spread increases.

Favorites and Underdogs

Favorites

Below are stats from teams favored in the same spread ranges used above:

FAVORITES	GP	40+ FP	40+/GP	50+ FP	50+/GP
0-3 Pts	58	53	0.91	16	0.28
3-6 Pts	78	68	0.87	20	0.26
6-9 Pts	54	46	0.85	13	0.24
9-12 Pts	39	39	1.00	10	0.26
12+ Pts	11	11	1.00	6	0.55

Underdogs

Below are stats from underdog teams in the same spread ranges used above:

UNDERDOGS	GP	40+ FP	40+/GP	50+ FP	50+/GP
0-3 Pts	58	40	0.69	14	0.24
3-6 Pts	78	54	0.69	13	0.17
6-9 Pts	54	36	0.67	6	0.11
9-12 Pts	39	15	0.38	4	0.10
12+ Pts	11	4	0.36	0	0.00

The number of big performances by player’s on underdog teams are significantly lower than those favored. It looks as if blowout potential doesn’t impact a player’s ability to post a huge stat-line, but being expected to lose in a blowout should definitely push you away from a given option.

Spread with Over/Under

The last sub-section we’ll look at takes into account all combinations of both spread and over/under:

Table below is sortable. Click any column header to sort by that category

Spread	O/U	GP	40+ FP	40+/G	50+ FP	50+/G
(0-3)	(0-190)	9	12	1.33	7	0.78
(3-6)	(0-190)	13	21	1.62	5	0.38
(6-9)	(0-190)	5	6	1.20	1	0.20
(9-12)	(0-190)	3	4	1.33	0	0.00
(12+)	(0-190)	1	0	0.00	0	0.00
(0-3)	(190-195)	9	10	1.11	2	0.22
(3-6)	(190-195)	12	17	1.42	5	0.42
(6-9)	(190-195)	5	3	0.60	1	0.20
(9-12)	(190-195)	5	5	1.00	3	0.60
(12+)	(190-195)	0	0		0
(0-3)	(195-200)	12	16	1.33	4	0.33
(3-6)	(195-200)	17	26	1.53	6	0.35
(6-9)	(195-200)	11	19	1.73	6	0.55
(9-12)	(195-200)	5	6	1.20	3	0.60
(12+)	(195-200)	5	6	1.20	2	0.40
(0-3)	(200-205)	7	10	1.43	0	0.00
(3-6)	(200-205)	17	29	1.71	10	0.59
(6-9)	(200-205)	13	17	1.31	0	0.00
(9-12)	(200-205)	14	18	1.29	4	0.29
(12+)	(200-205)	1	0	0.00	0	0.00
(0-3)	(205-210)	14	30	2.14	11	0.79
(3-6)	(205-210)	8	14	1.75	1	0.13
(6-9)	(205-210)	7	17	2.43	5	0.71
(9-12)	(205-210)	5	8	1.60	0	0.00
(12+)	(205-210)	2	4	2.00	1	0.50
(0-3)	(210-215)	3	7	2.33	2	0.67
(3-6)	(210-215)	9	13	1.44	5	0.56
(6-9)	(210-215)	8	13	1.63	3	0.38
(9-12)	(210-215)	5	9	1.80	2	0.40
(12+)	(210-215)	1	3	3.00	2	2.00
(0-3)	(215+)	4	8	2.00	4	1.00
(3-6)	(215+)	2	2	1.00	1	0.50
(6-9)	(215+)	5	7	1.40	3	0.60
(9-12)	(215+)	2	4	2.00	2	1.00
(12+)	(215+)	1	2	2.00	1	1.00

Again, the highest 40+FP/Gm and 50+FP/Gm averages come from a split with just one game (12+ spread, 210-215 O/U), which is probably inconclusive.
Of the four games played with 215+ over/unders and less than 3 point spreads, 8 players posted 40 or more fantasy points, which is to be expected.
The best range in terms of sample size and data seems to be a 3 point spread between 205 and 210 point over/unders, where over 2 players per game put up 40+ fantasy points.
In terms of 50+ FP games, it looks like a closer spread is more important than the over/under. 0.78 50+/game in the lowest over/under games (0-190 points) with a 3 point spread or less.