FairValue

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

Marsà

CBSpain · KV Mechelen

№ 563139Established €3.9M −0.10

Player dossierPro League

JoséMarsà

CBCentre-BackDefender

Club
KV Mechelen
League
Pro League
Nationality
Spain
Age
24
Height
185 cm
Foot
Left
Valued
4 Jun 2026

Reading the valuation

The market values Marsà at €3.5M. Model A, which never saw Marsà during training, estimates €3.9M: the market value is 9% below that estimate.

That is a factor of ×1.10. 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 €5.6M, 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.

▼ −0.10A €3.9M▼ −0.47B €5.6M
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
62
Minutes
4,870
Goals
1
Assists
4
Started
56/62
Min / app
79
Cards
8Y 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 Marsà…

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 €3.5M

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €3.5MModel A €3.9M

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

José Marsà's percentiles among defenders: Goals per 90 39th, Assists per 90 69th, Minutes, two years 82nd, Starts 70th, Minutes, last 365 days 78th, European club minutes 30th39thGoals69thAssists82ndMinutes70thStarts78thRecent30thEurope

Dashed ring: the defender median (50th percentile)

Minutes, two years

Total club minutes in the two-year window: how much the player was used.

4,870 this player2,860 defender median82nd percentile

451peer deciles · median line · this player ●9,111

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
€200k
Mar 2021
Peak
€3.5M
Jun 2026
Model target
€3.5M
Jun 2026
Valuations
13
4 club changes
Jun 2026€3.5MKV MechelenValuation the model is trained to reproduce

Jun 2026: €3.5M, KV Mechelen. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2021-03-19€200kFC Barcelona U19
2021-06-30€200kFC Barcelona U19
2022-09-16€500kSporting CP
2022-11-01€2MSporting CP
2023-06-14€2MSporting Gijón
2023-10-13€1.5MFC Andorra
2023-12-20€1MFC Andorra
2024-06-24€800kFC Andorra
2024-12-11€1.2MKV Mechelen
2025-03-26€2.2MKV Mechelen
2025-06-12€3MKV Mechelen
2025-12-10€3MKV Mechelen
2026-06-04€3.5MKV Mechelen

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
−0.095

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 →

Pro League350 players · median €1.8M

Valued above 73% of the 350 Pro League players.

€100k€750k€5M€30M€3.5MSee them in the Explorer →

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

Valued above 63% of the 2,065 defenders.

€20k€200k€2M€20M€3.5MSee them in the Explorer →

Where Marsà 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).