FairValue

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

Kabongolo

CBFrance · Livingston FC

№ 802221Emerging €236k −2.24

Player dossierPremiership

BrooklynKabongolo

CBCentre-BackDefender

Club
Livingston FC
League
Premiership
Nationality
France
Age
23
Height
195 cm
Foot
Right
Valued
20 May 2026

Reading the valuation

The market values Kabongolo at €25k. Model A, which never saw Kabongolo during training, estimates €236k: the market value is 89% below that estimate.

That is a factor of ×9.43. 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 €661k, 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.

▼ −2.24A €236k▼ −3.27B €661k
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
12
Minutes
840
Goals
2
Assists
0
Started
10/12
Min / app
70
Cards
2Y 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 Kabongolo…

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 €25k

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €25kModel A €236k

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

Brooklyn Kabongolo's percentiles among defenders: Goals per 90 99th, Assists per 90 17th, Minutes, two years 8th, Starts 52nd, Minutes, last 365 days 24th, European club minutes 30th99thGoals17thAssists8thMinutes52ndStarts24thRecent30thEurope

Dashed ring: the defender median (50th percentile)

Goals per 90

Club goals per 90 minutes played in the two years to the valuation date.

0.21 this player0.03 defender median99th percentile

0.00peer deciles · median line · this player ●0.41

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
Oct 2025
Peak
€25k
Oct 2025
Model target
€25k
May 2026
Valuations
3
1 club change
May 2026€25kLivingston FCValuation the model is trained to reproduce

May 2026: €25k, Livingston FC. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2025-10-09€25kArbroath FC
2025-12-10€25kArbroath FC
2026-05-20€25kLivingston FC

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
−2.244

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 →

Premiership311 players · median €400k

The joint lowest observed value among 311 Premiership players.

€20k€150k€1M€7.5M€25kSee them in the Explorer →

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

The joint lowest observed value among 2,065 defenders.

€20k€200k€2M€20M€25kSee them in the Explorer →

Where Kabongolo 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).