FairValue

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  • EnvironmentOverviewWhat FairValue measures, what it found, where to go next.
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João

Ferreira

RBPortugal · AS Saint-Étienne

№ 481623Established €3.7M −0.22

Player dossierLigue 1

JoãoFerreira

RBRight-BackDefender

Club
AS Saint-Étienne
League
Ligue 1
Nationality
Portugal
Age
24
Height
185 cm
Foot
Right
Valued
11 Dec 2025

Reading the valuation

The market values Ferreira at €3M. Model A, which never saw Ferreira during training, estimates €3.7M: the market value is 20% below that estimate.

That is a factor of ×1.25. Model A's typical held-out miss is ×1.50 either way, so this gap is within its usual error.

Without league and club, Model B estimates €5M, further from the market. Model B is usually further off (typical miss ×2.07): league and club explain much of how the market prices players.

A gap describes the model's arithmetic for this player's inputs, not what the player is worth.

▼ −0.22A €3.7M▼ −0.50B €5M
Pitch length is a log value scale fitted to this player's figures. ● observed · ◇ Model A · dashed ◇ Model B · each arc is a residual, log(observed) − log(estimate).
Apps
51
Minutes
3,155
Goals
0
Assists
2
Started
32/51
Min / app
62
Cards
13Y 0R

Club matches, two years to the valuation date

The Valuation Journey

What moves Model A

Asking the prediction API to explain Model A for Ferreira…

SHAP describes the model's arithmetic for this player's inputs, not what causes market value. Model B can be explained only by the live service; Model A also has a published explanation for the research players.

Model A vs Model B against the observed €3M

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €3MModel A €3.7M

Asking the prediction API…

Held-out estimates come from cross-validation, with this player outside the training data: the honest comparison. Served models were refitted on every player, this one included, so they sit closer to the market. Shaded band: Model A's typical miss (×1.50 either way).

Player traitspercentiles vs 2,065 defenders

João Ferreira's percentiles among defenders: Goals per 90 18th, Assists per 90 61st, Minutes, two years 56th, Starts 18th, Minutes, last 365 days 20th, European club minutes 80th18thGoals61stAssists56thMinutes18thStarts20thRecent80thEurope

Dashed ring: the defender median (50th percentile)

European club minutes

Share of minutes played in UEFA club competitions.

17% this player0% defender median80th percentile

0%peer deciles · median line · this player ●85%

No passing, progression or defensive actions exist in the dataset, so no trait claims to measure them.

Valuation history every Transfermarkt valuation on record

First valuation
€1M
Dec 2019
Peak
€4M
Dec 2024
Model target
€3M
Dec 2025
Valuations
14
6 club changes
Dec 2025€3MAS Saint-ÉtienneValuation the model is trained to reproduce

Dec 2025: €3M, AS Saint-Étienne. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2019-12-31€1MSL Benfica B
2020-04-08€900kSL Benfica B
2020-11-02€800kSL Benfica B
2021-06-29€850kSL Benfica B
2021-12-27€850kVitória Guimarães SC
2022-05-31€700kVitória Guimarães SC
2022-11-01€400kRio Ave FC
2023-06-01€400kWatford FC
2023-10-11€1MUdinese Calcio
2023-12-20€2MUdinese Calcio
2024-06-05€2MUdinese Calcio
2024-12-19€4MSC Braga
2025-05-30€3MSC Braga
2025-12-11€3MAS Saint-Étienne

Audit context group-level, not about this player

Audit group
UEFA
Population gap, Model A
+0.093 95% CI +0.063 to +0.124
This player, market vs held-out A
−0.221

The group comes from first-listed citizenship and is never a model input. Across the population, non-UEFA players' market values sit about 10% above Model A's held-out estimates, relative to UEFA players in the same leagues. One player's residual says nothing about that pattern (typical miss ×1.50), and none of it is evidence of discrimination: the target may itself be biased. Open the Fairness Audit

In context observed value among comparable players in this build

All players in the Terminal →

Ligue 1423 players · median €5M

Valued above 30% of the 423 Ligue 1 players.

€100k€750k€5M€30M€3MSee them in the Explorer →

Defenders, all leagues2,065 players · median €2M

Valued above 59% of the 2,065 defenders.

€20k€200k€2M€20M€3MSee them in the Explorer →

Where Ferreira appears

Watchlists and the comparison tray are kept in this browser only.

Near this valuation closest observed values: same league, then same position

Counts and ranks of observed Transfermarkt values only; model errors are never ranked here. Full player export: Every player in the modelling population (D-011).