Key Facts
- Closing Line Value is the price a gambler gets on a game, relative to the closing price.
- CLV can be measured in terms of probability, money or expected value.
- Positive CLV means the bettor “beat the market”.
Serious gamblers will keep track of more than just their wins, losses and size of their bankroll. One important measure of how successful a gambling strategy is working out is to track the Closing Line Value, or CLV.
It’s not enough to pick a winner and cash in. Hard-core gamblers—people who want to make a living at it—want to win their bets and beat the market as well. CLV is a way of measuring how successful they are at doing that.
The Ever-Changing Line
When a game or match is first made available for betting at a casino or offshore sportsbook, it is given an opening line. This is the bookmaker’s best guess at a team’s likelihood of winning while making sure the public is split 50/50.
The bookmaker usually knows their stuff, and the opening lines are generally fairly accurate, but most games don’t remain at their opening line for long. Almost immediately, they begin to move. That’s because the activity of gamblers putting money into the game will shift the line in one direction or another.
Sportsbooks want roughly equal betting on both sides of a line. Let’s say the Dallas Cowboys open as favorites in this week’s game. The point spread line may be set at Cowboys -3. If the majority of bettors think the Cowboys will be able to cover that and begin betting on them and giving the points, the line will move to make the Cowboys less desirable. It might move to Cowboys -4 or -5, meaning that you need to give up more points if you still want to pick them.
On the other hand, if more people are betting against Dallas, the line will move to make them a more desirable pick. Maybe it goes to -1 or even, in the hopes that giving up fewer points will entice people to pick them.
By game time, the line may have moved several points from where it opened. In general, we think of the closing line—the final line for a game before it starts—as the most accurate. That’s because it’s the result of everyone placing all their bets in one direction or the other.
Everyone has vote with their bankroll, and, regardless of what system each bettor used to determine who would win, the final line reflects all of that. It also reflects the most recent injury news and anything else that might impact the outcome.
So, What’s CLV?
Most gamblers don’t wait until the closing line to place their bets. They’ll make their pick in advance of that, meaning the closing line may be different from the line or odds they got. CLV is a way of comparing the two. A gambler hopes that he or she was able to get their money down before the line changed for the worse.
For example, If a gambler picked Dallas at -2, and then the line moved to -4, the gambler got positive CLV. The market determined that Dallas was four points better, but the gambler only had to give up two points.
On the other hand, if the gambler got Dallas at -2 and the game closed at even, the gambler got negative CLV.
Why Does It Matter?
Like most things in gambling, Closing Line Value adds up over the long haul. Beating the closing line by a half point here or a full point there may not matter in many games. Let’s say Dallas won by 10. You’d have had a winning bet regardless of when you placed it. But on occasion, Dallas will win by a field goal. Then, it makes a very big difference whether you got your bet down at -2 or -4. You can also look at CLV for money lines, in which case you’d be earning a few more dollars on winning bets and losing a little less on losing bets when you get positive CLV.
How Do You Calculate It?
There are three ways to look at CLV: In terms of win probability, dollars and cents or expected value.
Dollars and Cents
Looking at moneyline odds, the dollars and cents method is the easiest to calculate. Essentially, you subtract the closing line from the line you bet. Since those are based on $100 bets, you divide by 100 to get your CLV in “cents”.
For example, if you bet the Lakers at -130 and the line closes at -140, your CLV is 10 cents. (The difference between the lines is 10). Similarly, if you take the Nuggets at +180 and it closes at +170, you get 10 cents of CLV.
However, not all differences in moneyline are created equal. If a line moves from +300 to +250, that’s a 50-cent CLV. So is moving from +150 to +100.
That brings us to the second way of measuring CLV: win probability.
Win Probability
It is possible to convert moneylines into implied win probabilities, either by hand or by using any one of the dozens of online calculators that will do it for you. For instance, if you bet a team at -120, and it moves to -170 at close, rather than talk about the 50 cents of CLV you got, you can calculate the win probabilities.
In this case, -120 moneyline translates to a 54.55% win probability. -170 translates to 62.96%. So by getting your bet down at -120, you got a CLV of 8.41% in win probability (the difference between the two probabilities.
Expected Value
The expected value takes that difference in win probability and divides it by the win probability you earned with your bet. So in the above example, you’d have 8.41% divided by the 54.55% probability from your bet. That equates to a 15.4% expected value increase as your CLV.
