FairValue

Checking model

Esc

  • EnvironmentOverviewWhat FairValue measures, what it found, where to go next.
  • EnvironmentTerminalExplore, compare and track players; market, league and model views.
  • EnvironmentStoriesValuations, head-to-heads and research findings, told as stories.
  • TerminalPlayer ExplorerSearch, filter and sort the player export.
  • TerminalComparison StudioTwo to four players on one scale.
  • TerminalWatchlistsNamed collections, kept in this browser.
  • TerminalMarket LandscapeHow observed value is distributed, and where the model drifts.

↑ ↓ to move · Enter to open · Esc to closeLoading player index…

Bo De

Kerf

CBBelgium · FCV Dender EH

№ 790238Emerging €306k +0.67

Player dossierPro League

Bo DeKerf

CBCentre-BackDefender

Club
FCV Dender EH
League
Pro League
Nationality
Belgium
Age
22
Height
191 cm
Foot
Right
Valued
4 Jun 2026

Reading the valuation

The market values Kerf at €600k. Model A, which never saw Kerf during training, estimates €306k: the market value is 96% above that estimate.

That is a factor of ×1.96. Model A's typical held-out miss is ×1.50 either way, so this gap is larger than its usual error.

Without league and club, Model B estimates €535k, closer to the market here, although it is usually further off (typical miss ×2.07).

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

▲ +0.67A €306k▲ +0.11B €535k
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
8
Minutes
458
Goals
0
Assists
0
Started
5/8
Min / app
57
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 Kerf…

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 €600k

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €600kModel A €306k

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

Bo De Kerf's percentiles among defenders: Goals per 90 18th, Assists per 90 17th, Minutes, two years 0th, Starts 18th, Minutes, last 365 days 10th, European club minutes 30th18thGoals17thAssists0thMinutes18thStarts10thRecent30thEurope

Dashed ring: the defender median (50th percentile)

European club minutes

Share of minutes played in UEFA club competitions.

0% this player0% defender median30th 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
€250k
Apr 2025
Peak
€600k
Dec 2025
Model target
€600k
Jun 2026
Valuations
4
1 club change
Jun 2026€600kFCV Dender EHValuation the model is trained to reproduce

Jun 2026: €600k, FCV Dender EH. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2025-04-24€250kK Lierse SK
2025-10-15€400kK Lierse SK
2025-12-18€600kK Lierse SK
2026-06-04€600kFCV Dender EH

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
+0.675

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 13% of the 350 Pro League players.

€100k€750k€5M€30M€600kSee them in the Explorer →

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

Valued above 22% of the 2,065 defenders.

€20k€200k€2M€20M€600kSee them in the Explorer →

Where Kerf 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).