Resources

Football forecasting glossary

Plain-English definitions of the probabilities, models, data rules and scores behind our predictions, from 1X2 to two-source rule. Each term links to the page where it is used.

38 terms

#

Markets

1X2

The three possible 90-minute results: home win (1), draw (X) or away win (2).

Every forecast on the site starts with these three probabilities, which always add up to 100%. Extra time and penalties are not included.

A

Evaluation

Accuracy (1X2 hit rate)

The share of graded matches where the most likely result was the one that happened.

Accuracy is easy to read but ignores how confident a forecast was, so we always show it next to RPS and log loss. Around 50–55% is typical for good football models because draws are hard to call.

Accuracy = correct picks / graded matches

Models

AI analyst

Claude (Anthropic) or Codex (OpenAI), used to gather sourced team news, give their own forecast and draft match analysis.

In version 1 their forecasts run in shadow: they are graded but do not change the published probability. Written analysis is checked by a human editor before it is published.

B

Evaluation

Backtest (walk-forward)

A test of a model on past seasons, where each forecast uses only data that was available before that match.

Backtest numbers are shown separately from live results and are never mixed into the track record of published forecasts.

Evaluation

Base rate

A simple benchmark that always predicts the league's long-run share of home wins, draws and away wins.

A model is only useful if it beats the base rate on the same matches. We report it next to every model in the track record.

Markets

Both teams to score (BTTS)

Whether both sides score at least once in the 90 minutes.

We derive it from the same score grid as the 1X2 probabilities, so the numbers are always consistent with each other. It is the hardest market to beat a simple rule on.

P(BTTS) = 1 − P(home scores 0) − P(away scores 0) + P(0–0)

Evaluation

Brier score

The squared difference between the forecast probabilities and what happened, added across home, draw and away.

Lower is better. A perfect forecast scores 0 and the worst possible scores 2. It punishes confident misses more than cautious ones.

Brier = Σ (pᵢ − oᵢ)²

C

Evaluation

Calibration

Whether forecast probabilities match how often things actually happen.

If we give 100 outcomes a 60% chance, about 60 of them should happen. Calibration is checked in bands (for example 50–60%) with a 95% interval, because small samples move a lot.

Evaluation

Confidence interval

A range that shows how much a number could move by chance with the sample we have.

We show 95% intervals for accuracy and RPS. When the interval is wide, treat the headline number with care.

Probabilities

Confidence tier

Our label for how strong the most likely result is: High (65% or more), Medium (50–64%) or Low (under 50%).

Tiers describe the probability, not a promise. High picks are still expected to miss now and then, and we publish how often each tier has been right.

Markets

Correct score

The probability of one exact final score, such as 1–1 or 2–1.

Even the most likely score usually has a probability around 10–14%, so exact scores miss most of the time. We show them neutrally and never grade the site on them alone.

Evaluation

Coverage

The share of eligible fixtures that received a published forecast.

A model can look better by skipping hard matches. Coverage shows how many we skipped and why (postponements, missing data).

Coverage = published eligible forecasts / eligible fixtures

D

Data and locking

Data batch

One scheduled run that collects, checks and publishes new data.

The site updates in batches, not live. Each page shows the time of the latest batch and the next one.

Data and locking

Data cutoff

The moment after which no new information can enter a forecast.

For published forecasts the cutoff is the lock, normally 24 hours before kickoff. News that arrives later is not reflected in the locked numbers.

Models

Dixon-Coles model

A goals model that adjusts the Poisson model for the extra 0–0, 1–0, 0–1 and 1–1 results seen in real football.

It is the core of our statistical layer. Older matches count less (time decay), and team strengths are pulled towards the league average when there is little data.

τ(0,0) = 1 − λₕλₐρ · τ(1,1) = 1 − ρ

E

Evaluation

Early sample

Our label for any record built on fewer than 100 graded matches.

Small samples swing a lot, so we show the numbers but do not compare them as if they were settled.

Models

Elo rating

A team strength number that goes up after good results and down after bad ones, by more when the result was unexpected.

We use it as one input and as a simple benchmark ("Elo only") in the track record. Home advantage is added before the comparison.

Expected = 1 / (1 + 10^(−(Rₕ + H − Rₐ)/400))

Markets

Expected goals (xG)

The number of goals a team would be expected to score from the chances it created.

Our version 1 model does not use xG: the shot data we could use is not available under a licence that allows public use. The "expected goals" shown on match pages are model goal averages (λ), not xG.

F

Probabilities

Favourite

The side with the highest win probability.

A favourite at 48% is expected to win slightly less than half the time. Being the favourite is not the same as being likely to win.

G

Evaluation

Grading

Scoring a locked forecast against the 90-minute result. Conflicting sources hold the score; unavailable confirmation allows single-source grading.

Every published forecast is graded, misses included. Postponed matches are voided and listed in the exclusion log.

H

Models

Home advantage

The extra chance of winning that playing at home gives, on average.

It varies by league and over time, so the model fits it from recent seasons instead of using a fixed number.

I

Probabilities

Implied probability

The probability suggested by betting odds.

For decimal odds it is 1 divided by the odds. Bookmaker odds include a margin, so the implied probabilities add up to more than 100%. We do not use odds in version 1.

Implied probability = 1 / decimal odds

L

Data and locking

Ledger

Our public list of every locked forecast, with its SHA-256 fingerprint.

Anyone can download the files and recompute the hash to check that a forecast was not changed after it was locked.

Data and locking

Lock (forecast lock)

The point, normally 24 hours before kickoff, when a forecast is frozen and fingerprinted.

Before the lock a match shows "Forecast not yet locked". After it, the probabilities cannot change.

Evaluation

Log loss

A score based on the probability given to the result that actually happened.

Lower is better. It punishes very confident misses heavily, which makes it a good check on over-confidence.

Log loss = −ln(p of the actual result)

M

Models

Model version

The exact set of parameters and rules that produced a forecast.

Every locked forecast records its model version. A new version is released with a changelog and is never applied to past forecasts.

O

Markets

Over/Under 2.5 goals

Whether the match has three or more goals (over) or two or fewer (under).

Like BTTS it comes from the same score grid as the 1X2 probabilities, and we compare it with the simple rule of always picking the more common side.

Probabilities

Overround (bookmaker margin)

How far the implied probabilities from a set of odds add up to more than 100%.

The excess is the bookmaker's margin. It has to be removed before odds can be compared with model probabilities.

Overround = Σ (1 / odds) − 1

P

Models

Poisson distribution

A way to turn an average number of goals into the chance of 0, 1, 2 or more goals.

Each team gets an expected goals figure (λ) for the match; the Poisson formula, adjusted by Dixon-Coles, turns the two figures into a full score grid.

P(k goals) = λᵏ e^(−λ) / k!

Probabilities

Probability

How often an outcome would happen across many matches like this one.

A 60% home win means the home side would win about 60 of 100 identical matches, not that it will win this one.

R

Evaluation

Ranked probability score (RPS)

Our main grading score: how far the cumulative forecast was from the cumulative result.

It respects the order home – draw – away, so calling a draw when the home side won is penalised less than calling an away win. Lower is better.

RPS = ½ [(P₁ − O₁)² + (P₁ + P₂ − O₁ − O₂)²]

S

Models

Score grid

The table of probabilities for every exact score, for example 0–0 to 6–6.

Win, draw and loss, over/under, BTTS and correct score are all read from this one grid, so they never contradict each other.

Models

Season simulation

Playing out the rest of a season thousands of times with the model to estimate final positions.

We run 10,000 simulations each week and report the chance of each finishing position, title and top four.

Data and locking

SHA-256 hash

A fingerprint of a file: change one character and the hash changes completely.

We hash each locked forecast and publish the hash, so the forecast cannot be edited quietly afterwards.

Models

Shadow model

A model whose forecasts are recorded and graded but not published as the main number.

Our AI layer runs in shadow until it beats the statistical model on enough matches under rules fixed in advance.

Data and locking

Statistical forecast

A match with model probabilities but no reviewed analysis, or where team news has not been checked for that match yet. Match lists mark the second case as “Team news pending”.

The numbers are published as usual: the statistical model does not use team news or written analysis. Matches without enough data for the model show no probabilities at all.

T

Data and locking

Team news dossier

The sourced list of injuries, suspensions and other news collected for a match before the lock.

Each item needs a dated source and a link. A match without a verified dossier is marked "limited context".

Data and locking

Two-source rule

Checking a result against a second source. Scores from our data feed are compared with an independent second source; open historical data can confirm them later.

Disagreements are held for review. If the second source is unavailable, grading proceeds with one source and is counted as single-source coverage.

See the terms in use

The methodology puts these pieces together: data, model, locking and grading.

For information and entertainment only. Not betting advice. 18+. Predictions are probabilities, not certainties. Responsible gambling