Expected goals are not a predicted final score
By RinkSignal Reviewed
How can a team create better chances and still lose?
Expected goals describe the average scoring value of chances, not what the scoreboard must say. A missed open chance still has value in the chance-quality model; a goal from a difficult angle still counts as one actual goal.
| Illustrative chance | Modeled scoring probability | Expected goals |
|---|---|---|
| Lower-quality attempt | 5% | 0.05 |
| Higher-quality attempt | 35% | 0.35 |
| Combined | Not a single-shot probability | 0.40 |
Separate recorded chances from a pregame forecast
Event xG evaluates recorded chances. Pregame expected goals estimate how much each team will score before those chances happen. They answer related but different questions. RinkSignal calculates its event xG from NHL events using its own model; it does not import another analytics site's xG ratings.
On-ice xGF and xGA describe chances for and against during a player's covered ice time. They include teammates and opponents. Read them together and check that the coverage is comparable before attributing the entire difference to one skater.
Why the matchup favorite can lose
RinkSignal's Matchup tool calculates win probabilities from independent Poisson scoring distributions using each side's expected goals. It accounts for tied regulation scores through an overtime/shootout allocation. A favorite still has a distribution of possible results, including losses.
The 1,000 simulated games supply likely-score examples. The main win probabilities come from the scoring distributions directly, not the fraction of wins in that particular simulation run. This removes simulation noise from the headline probability, not uncertainty in player talent or lineup assumptions.
Use a lineup change as a question
Compare the same teams with the same home-ice and rest settings, change one lineup assumption, then examine the expected-goals and probability difference. The result is a model scenario, not evidence that a coach would get exactly that outcome.
Default lines may be estimates when current, validated lineup reports are unavailable. Injuries, scratches and the starting goalie can matter. Check those assumptions before treating a pregame number as settled.
Do not mix different model questions
Matchup uses a separately versioned talent model from the season playoff forecast. The chance of winning one selected game is not the chance of reaching the playoffs. Home's linked matchup should agree with Matchup when the snapshot, teams, lineups, home ice and rest settings match.
For goalies, goals saved above expected compares expected goals against with goals actually allowed in the matching event sample. Missing events cannot safely be combined with an unmatched full-season goals-against total.