Evaluating surprising results

SoccerSTATS.com - updated on: 7 Aug 2025

As a low-scoring game, football can produce match results that can seem surprising. The strongest team on-paper may lose, even the strongest team on the pitch may lose. Each football weekend carries its load of surprises, big or small. Let's try to quantify how much of a surprise a given match outcome could represent.

The final whistle blows and the fans realize what has just happen. This is it. That last minute goal. That home defeat that nobody seems to have seen coming, and certainly not at the league leaders' stadium. This is a known feeling though, it happened before. But this time this feels like a bigger surprise. Rightfully so? Last year's defeat was against the team ranked 4th in the league. This time it was against the 8th. Yet the winners may be ranked in 8th position in the league, they also have an impressive record on the road this season, so maybe this could be less of a surprise after all.

Evaluating match outcomes, as opposed to specific scorelines

Of all the surprising results - and in this article, we'll be discussing "outcomes" (like a win or a draw) as opposed to results with a specific scoreline - some can be deemed more surprising than others. If we were to calculate how much of a surprise a given match outcome could represent, we'll have to come up with a set of criteria.

Choosing the criteria

Let's say we want to come up with a value representing the "surprise-level" of a particular outcome. To calculate such value, we'll be taking into account the same type of indicators covered in other articles in this blog related to team performance evaluation: home and away Points Per Game (PPG).

The goal is not to obtain a value that would absolutely define with a number what we call a "surprise", as a "surprise" is also mainly a feeling and will always be subjective to some degree.

To a fan of the winning team, the "surprising" outcome may represent less of a surprise than to a fan of the high-profile team that has been defeated. The idea is to compare matches with each other, so that we can calculate values by which we could say something like: "According to these criteria, the outcome of this match is more surprising than the outcome of that match."

Outlining a formula

In line with the Run-in analysis, where we use the opponents' Points Per Game value to evaluate how "valuable", in terms of performance, a win could be, we will determine the outcome surprise-level for a given match based on the teams Points Per Game.

To calculate how much of a "surprise" is a team's outcome for a specific match, we will consider the difference between the number of points picked up by the team in that match the average number of points per game picked up by the team on average before the match, either at home or away, depending on where the team has played the match we are looking at.

We come up with a "difference" value for each team and we'll then take the average of those two values. We divide the result by the total number of possible points (3) and then multiply that result by 100.


Let's take the following match as an example:

Team 1 vs Team 2, final score 3-2 (so the outcome was: HOME WIN).


Step 1: pre-match Points Per Game values

Team 1 Points Per Game at home before the match: 2.11
Team 2 Points Per Game away before the match: 0.60

As the outcome for the match was a HOME WIN, Team 1 has picked up 3 points, and Team 2 has picked up 0 point.


Step 2: difference between points picked up and Points Per Game

Difference for Team 1: ABS(2.11 - 3) = 0.89
Difference for Team 2: ABS(0.60 - 0) = 0.60


Step 3: average of both Difference values

Average value = (0.89 + 0.60) / 2 = 0.745


Step 4: Average value relative to a 3-point scale

Outcome Surprise Level = (0.745 / 3) * 100 = 24.8


The scale goes from 0 (less surprising) to 100 (more surprising).

Avoiding pitfalls

This formula calculates the Outcome Surprise Level using only each team's home or away Points Per Game (PPG). It doesn't consider all matches each team has played, specifically ignoring the home team's away games and the away team's home games.

Furthermore, the formula is applied to the final match outcome (home win, away win, or draw), not the exact score. For example, a 1-0 and a 5-0 victory are both treated as a home win, and the size of the winning margin does not change the calculated Outcome Surprise Level.

Example

You can view an example of the Outcome suprise-level table for matches of the Serie B or the Bundesliga.