Championship · Tuesday, 1 September 2026 · 19:45. Final score 0–2 (half-time 0–1). Before kick-off we rated it 52% over 2.5 goals — the match finished with 2, so that call missed. That rating was frozen into a version-controlled ledger before the game and has not been touched since.
Open this match in the app →| Market | Yes | No | Our call |
|---|---|---|---|
| Over 2.5 goals | 52% | 48% | Over |
| Over 3.5 goals | 29% | 71% | no pick |
| Both teams to score | 60% | 40% | Yes |
The result model puts Portsmouth at 31%, the draw at 25% and Derby at 44%, from expected goals of 1.29 and 1.59.
| Market | Price | Implied | Our rating | Edge |
|---|---|---|---|---|
| Over 2.5 goals | 2.00 | 47% | 52% | +4% |
| Under 2.5 goals | 1.80 | 53% | 48% | -4% |
| Both teams to score | 1.80 | 51% | 60% | +8% |
Implied percentages have the bookmaker's margin removed, so they add to 100 and can be compared with our rating directly. Edge is simply the gap between the two. A positive edge means our model thinks the outcome is likelier than the price suggests — it is not a tip, and a high probability with a negative edge is a poor bet however safe it looks. Prices are a pre-match snapshot from a single bookmaker and move constantly.
Match odds: Portsmouth 2.00, draw 3.30, Derby 3.60.
The league sets the starting point. Championship has produced over 2.5 goals in 52% of its matches, and that is where a team with no record of its own would sit.
Each side's own record. Portsmouth have 3 in 3 this season (1 of 1 at home), Derby 3 in 3 (1 of 1 away). Those records are pulled toward the league rate with the weight of about 32 matches — enough that two or three unusual games cannot swing a rating — giving 58% and 58%.
Last season still counts, briefly. With 3 and 3 games played this season, last season's rates are still blended in and fade out entirely by game 14 — the point at which our testing showed they stop adding accuracy. That moves the two figures to 46% and 53%.
The mix. Weighted 40% home side, 40% away side and 20% league — the split that beat every alternative across 30,582 matches of testing — that gives 50%.
Head to head. These sides have met 6 times in three years, producing over 2.5 goals in 50%. That nudges the number 10% of the way toward the head-to-head pattern — deliberately small, because fixtures change more than reputations do — landing on 50%.
Goal expectation. Separately a Poisson model built from attack and defence strength — using real expected-goals data where the league has it — puts this match at 55%, from expected goals of 1.29 for Portsmouth and 1.59 for Derby. Folding in 30% of that view gives 52%.
This breakdown is generated from the same inputs the rating uses, so it cannot describe a calculation we did not perform. The full model is set out in the methodology.
| Team | Games | O2.5 | O3.5 | BTTS |
|---|---|---|---|---|
| Portsmouth | 3 | 100% | 67% | 100% |
| Derby | 3 | 100% | 33% | 67% |
More: Portsmouth season stats · Derby season stats · Championship table and form. Ratings are calibrated probabilities, not tips — a 60% call is expected to miss two times in five.