What does it mean if a confidence interval includes zero?

It means the data collected so far cannot rule out "no real effect" as an explanation for the result. A positive average with an interval that includes zero is not proof that the effect is fake. It is a statement that the sample is not large enough yet to be sure either way.

Is a positive average enough to say a betting strategy works?

Not on its own. A positive average is a point estimate, a single best guess. Whether that guess is reliable depends on the confidence interval around it, which is a function of sample size and variance, not just the direction of the average.

Why does ServedBets publish a confidence interval alongside its CLV number?

Because the average alone invites treating an early, noisy result as settled. Publishing the interval, and saying so when it still includes zero, states exactly how much the current sample can and cannot prove.

Does a wide confidence interval mean the underlying strategy is bad?

No. A wide interval usually means the sample is small or the outcome is high-variance, not that the true effect is weak or absent. It means more data is needed before the number can be trusted either way. On its own it says nothing about direction.

What a Confidence Interval Means in a Betting Record

Our results page shows an average closing line value next to a 95% confidence interval. At the time of writing, 29 September 2026, that interval still includes zero. Both facts are true at once, and neither one is the whole story on its own. The live figures are on the results page; this article is about how to read them.

What a confidence interval is

A single average, whether a win rate, a mean CLV or an ROI, is a point estimate: one number standing in for a range of values the true figure could plausibly take. A confidence interval is that range, computed from the sample size and the spread of the data. A 95% confidence interval means that if you repeated the same measurement many times, about 95% of the intervals you computed would contain the true value.

It is not a claim that there is a 95% chance the true value sits inside this particular range. That is a common but technically incorrect shorthand. The statement is about the reliability of the method, given how much data went into it.

Why the interval matters more than the average

Two identical averages can mean very different things. A mean CLV of +2 percentage points built from a handful of bets and one built from several thousand are not equally trustworthy claims, even though the headline figure is the same. The interval tells you which of the two you are looking at.

That is why a positive average and an interval that includes zero do not contradict each other. They describe the same fact: the point estimate leans positive, but the sample collected so far cannot rule out zero, or even a small negative true effect, as consistent with the data.

How we read our own number

Two things are worth knowing about our CLV figure, and both are on the results page with their current values.

It only covers picks with a measured closing price. Since October we only count a price recorded within two hours of the start, and not every pick has one. The figure is therefore based on a subset of all tracked picks, and picks without a closing price are left out rather than guessed.
It is marked unconfirmed for as long as the interval includes zero. We do not report it as a settled result until the interval excludes zero.

There is one more nuance. A cruder test counts only whether each pick beat the closing price and ignores by how much. On the strictly measured picks that share is currently around one half, which is exactly what you would expect with no edge at all. That test throws away the size of each beat, so it does not replace the interval, and it shares the subset problem above.

Reporting the beat rate and the interval together is a different claim from “it is working”. Right now neither one shows an edge, and leaving out the interval would quietly overstate how settled any result is.

What would narrow the interval

An interval narrows with the square root of the sample size, holding the underlying variance roughly constant. Four times as many measured picks halves its width, ten times as many cuts it to about a third. There is no shortcut: an interval does not become more convincing because a few more weeks look good, only because n gets larger. Until then its width is doing useful work: it says “wait for more data”, which is more informative than either a bare average or false certainty in either direction.

So nothing about the current figure should be read as a confirmed edge or a debunked one. It is an undecided result, labeled as such, and the right move is to keep tracking rather than round it up or down to fit a cleaner story.

How to read this on any track record

Ask whether an average comes with an interval at all. A bare average with no stated interval and no sample size gives you no way to judge how much to trust it.
Check whether the interval crosses zero before treating a positive average as proof. A positive estimate with an interval that includes zero is a promising early sign, not a confirmed result. The two get conflated constantly in betting content.
Do not mistake a wide interval for a weak effect. It usually reflects a small sample or naturally high-variance data. It says the estimate is imprecise, not that the true value is small.
Watch how the interval moves over time, not just the average. An interval that keeps narrowing around a positive value as data arrives is much stronger evidence than a single positive snapshot.

What this means in practice

A confidence interval is not a hedge or a way of avoiding an answer. It is the answer, stated with the precision the data supports. Our strictly measured CLV figure currently sits close to zero and is not statistically distinguishable from no edge at all. Reporting a flattering average without that interval would be the misleading version of this update.

Related: closing line value explained covers what CLV measures and why it does not depend on who won.