FairValue

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

Keijzer

GKNetherlands · Heracles Almelo

№ 462285Emerging €473k −0.17

Player dossierEredivisie

Fabian deKeijzer

GKGoalkeeperGoalkeeper

Club
Heracles Almelo
League
Eredivisie
Nationality
Netherlands
Age
26
Height
193 cm
Foot
Right
Valued
28 May 2026

Reading the valuation

The market values Keijzer at €400k. Model A, which never saw Keijzer during training, estimates €473k: the market value is 15% below that estimate.

That is a factor of ×1.18. 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 €2.3M, 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.

▼ −0.17A €473k▼ −1.73B €2.3M
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
48
Minutes
4,410
Started
48/48
Min / app
92
Cards
1Y 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 Keijzer…

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 €400k

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €400kModel A €473k

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 485 goalkeepers

Fabian de Keijzer's percentiles among goalkeepers: Minutes, two years 71st, Starts 62nd, Minutes, last 365 days 36th, European club minutes 32nd71stMinutes62ndStarts36thRecent32ndEurope

Dashed ring: the goalkeeper median (50th percentile)

Minutes, two years

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

4,410 this player2,790 goalkeeper median71st percentile

450peer deciles · median line · this player ●9,210

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
€25k
Jan 2019
Peak
€1.5M
May 2025
Model target
€400k
May 2026
Valuations
20
2 club changes
May 2026€400kHeracles AlmeloValuation the model is trained to reproduce

May 2026: €400k, Heracles Almelo. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2019-01-21€25kFC Utrecht U21
2019-07-03€50kFC Utrecht U21
2020-06-29€325kFC Utrecht U21
2020-10-24€375kFC Utrecht
2020-12-31€375kFC Utrecht
2021-05-19€400kFC Utrecht
2021-10-12€400kFC Utrecht
2022-01-05€400kFC Utrecht
2022-03-17€600kFC Utrecht
2022-06-08€900kFC Utrecht
2022-11-11€800kFC Utrecht
2023-06-23€700kFC Utrecht
2023-12-15€600kHeracles Almelo
2024-05-31€500kHeracles Almelo
2024-10-14€800kHeracles Almelo
2024-12-17€1MHeracles Almelo
2025-05-28€1.5MHeracles Almelo
2025-12-02€700kHeracles Almelo
2026-03-11€500kHeracles Almelo
2026-05-28€400kHeracles Almelo

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
−0.168

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 →

Eredivisie425 players · median €1M

Valued above 18% of the 425 Eredivisie players.

€75k€500k€3M€20M€400kSee them in the Explorer →

Goalkeepers, all leagues485 players · median €1M

Valued above 21% of the 485 goalkeepers.

€20k€200k€2M€20M€400kSee them in the Explorer →

Where Keijzer 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).