Most sharp players think that beating closing lines is a key to winning at sports betting. For the most part, the closing line is efficient as it reflects the market's opinion in totality. In some so-called public games, that may not be the case, but public games are rarer these days as the market gets sharper. The majority of game lines are not influenced solely by public action, and the market gets it right. If you believe the closing line is the right line, then betting a better number than the closing line should lead to a winning record, and potentially beating the bookmaker's vig. In this article, I will apply this idea to college football. In particular, I will compare opening lines to closing lines to show how betting a better number than the closing line leads to profits.
Data
Recently I purchased College Football data from KOStats.com. KOStats.com sells databases that include betting lines and team statistics. I purchased the database that included College Football games from 2002 to 2010. While I had previously already compiled most of the same data, they had some variables that I was missing, two key variables being opening lines and opening totals. All opening lines and totals used in the tables and numbers in this article come from the KOStats.com College Football database.
Using Opening Prices to Bet into Closing Prices
The opening lines from KOStats.com's database come from CRIS, a respected offshore sportsbook that has been in business for many years. The linemakers at CRIS may have come up with the lines themselves or they could also have used help by looking at other sportsbooks' opening lines if they opened before CRIS or a separate line service. Since they have been in business for so long and still have a good reputation of paying winners (that cannot be said about all offshore sportsbooks, beware), I think it is a safe assumption they are themselves sharp handicappers. Additionally, CRIS has built a good reputation over the years as one of the first sportsbooks to post openers; they have plenty of experience setting new lines.
Hypothetically, let us assume they are bettors instead of bookmakers. If their initial opinion (which we see in the opening line) differs from the closing line, then they would have interest in making a bet. I used the database to pinpoint games where the difference between the opening and closing lines were different by two or more points. In those cases, I logged a hypothetical bet by the bookmakers versus the closing line. Unfortunately, these sharp bookmakers were only as good as flipped coins against closing lines.
Table 1: Opening Lines betting into Closing Lines
|
W |
L |
W% |
Pointspread |
782 |
757 |
50.8% |
Totals |
1005 |
1027 |
49.5% |
Combined |
1787 |
1784 |
50.0% |
These numbers show that opening lines has not beat closing lines in the past and leads to the conclusion that it is likely that opening lines will not beat closing lines in the future either. One smart group of handicappers (bookmakers in this case) has a tough time beating the market. This was not exactly a fair test as the closing line had more time and more information than the opening lines, but I still think it illustrates how much more efficient closing lines are than opening lines. Luckily for the bookmakers, they do not need to beat the market since they have the vig on their side.
Using Closing Prices to Bet into Opening Prices
Market participants set closing lines through their collective activity. As bets come in, bookmakers adjust their lines if they think it is necessary. Typically, there are three reasons bookmakers move lines:
- There is new information about teams, often injury news.
- There is a lot of action on one side.
- Respected bettors are betting one side.
The closing line reflects all public information and betting action. Different sportsbooks may have slightly different closing lines, but they will not be far apart due to scalpers, middlers and bettors looking for the best prices on the side they like. The closing line is tougher to beat, so it comes as no surprise that the closing line is more accurate than the opening line.
If someone could predict the market closing line when openers are first posted, how would he do? I logged a hypothetical bet when the closing line was different from the opening line by two or more points (the opposite of the exercise in the previous section). The closing line killed the opening line.
Table 2: Closing Lines betting into Opening Lines
|
W |
L |
W% |
Pointspread |
894 |
655 |
57.7% |
Totals |
1219 |
800 |
60.4% |
Combined |
2113 |
1455 |
59.2% |
These numbers show that closing lines would have defeated opening lines in the past. Based on this information, it is easy to conclude it is likely that closing lines will continue to beat opening lines in the future too. The market as a whole easily beats one group of sharp linemakers.
We Do Not Have Time Machines!
In order to beat opening lines, all we need to know is the closing lines. All we need is a time machine! We have now isolated a goal in sports betting. No, the goal is not to build a time machine. The goal is to try to beat closing lines consistently. If that goal is achieved, then the chance of an overall winning record is greatly increased. If you keep good records, you will be able to compare the line you bet into and the closing line. If you are not beating the closing line, then it is much tougher for you to have any edge over the bookmaker's vig.
Small Sample Sizes
Checking line movement is useful in analyzing small sample size records. For example, if you are 18-7 over 25 games, it is tough to tell if you have simply been lucky or if you actually have skill. It takes hundreds of games to become confident that the record indicates true talent. If lines are consistently moving in your direction, then that is a good sign. If you are not generally beating closing lines, then that increases the chance that good luck was a major factor. Gamblers, even good ones, are often impatient. It takes a long time to accumulate enough bets to evaluate records. Instead of being fooled by small sample sizes, one can use line movement performance as confirmation or lack thereof.
Reality
In practice, it is impossible to beat the closing line in every game. Table 2 shows a result that is not possible to duplicate in reality. Even the best handicappers will see the market move against him sometimes. In practice, a handicapper still needs to beat the closing line, but he does not have to beat it all the time in order to have a winning record.
Table 3 shows a hypothetical handicapper who beats closers by two or more points 25% of the time, but also loses to closers by two or more points 5% of the time. The remaining 70% of the time, there is no line movement. When he does beat closers, he wins at the rate shown in Table 2 - 59.2%. When the closers beat him, he wins at 40.8%. When there is no line movement, he is a small loser versus -110 lines. While this is a simple example, the distribution shown is closer to reality for a good handicapper than Table 2.
Table 3
|
Percentage |
Expected Win% |
Beats closers by 2 or more points |
25% |
59.2% |
Gets no line movement |
70% |
52.0% |
Loses to closers by 2 or more points |
5% |
40.8% |
Total |
100% |
53.2% |
Putting the numbers together shows the handicapper wins at a 53.2% rate. It is a winning record but not as impressive as shown in Table 2. However, this record is indeed very impressive because it is very difficult to beat closing lines by two or more points 25% of the time. I think this illustrates how difficult winning at sports betting can be, as well as how important it is to shop for the best lines and pay low vigs.
A Recent Real-life Example
This summer, a friend of mine had a nice baseball season betting overnight lines. He won 100 and lost 78. The average line was -105.6. He wondered what I thought of his record. How sure should he be that he is really beating the game and will continue to do so? That is a tough question to answer, but I thought a good exercise was for him to compare his bet prices versus the closing prices.
He found that the average fair closing price for the games he bet was -107.2. He was only beating the closing price by 1.6 cents on the money line. To me, that shows how lucky he was to amass a 100-78 record, when his true edge relative to the closing line was less than 0.5% per game. He may be a long-term winner in baseball, but in my opinion, he cannot be too confident and needs more games under his belt. With more games, not only will he have a bigger W-L sample size, but he will also have more games to compare line movement.
Conclusion
The goal is to beat closing lines, that is, to make bets at prices that are better than the closing lines. One way to help achieve this goal is to bet into opening lines, as they are more vulnerable. If you had a crystal ball and can see the closing line, then you will be swimming in profits. However, betting into opening lines does little good unless you actually do wind up with a better price than the closing line. In the short term, focus on beating the closing line. Do not worry about actual wins and losses. If you consistently beat the closing line, then the profits will come eventually.
