FairValue

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  • 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.

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Portrait of Josh Acheampong

Josh

Acheampong

RBEngland · Chelsea FC

№ 1004708Elite €22.5M +0.10

Image: FootyLogos

Player dossierPremier League

JoshAcheampong

RBRight-BackDefender

Club
Chelsea FC
League
Premier League
Nationality
England
Age
20
Height
190 cm
Foot
Right
Valued
3 Jun 2026

Reading the valuation

The market values Acheampong at €25M. Model A, which never saw Acheampong during training, estimates €22.5M: the market value is 11% above that estimate.

That is a factor of ×1.11. 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 €13.4M, 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 €22.5M▲ +0.63B €13.4M
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
35
Minutes
1,554
Goals
2
Assists
0
Started
17/35
Min / app
44
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 Acheampong…

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 €25M

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €25MModel A €22.5M

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

Josh Acheampong's percentiles among defenders: Goals per 90 91st, Assists per 90 17th, Minutes, two years 24th, Starts 6th, Minutes, last 365 days 41st, European club minutes 82nd91stGoals17thAssists24thMinutes6thStarts41stRecent82ndEurope

Dashed ring: the defender median (50th percentile)

Goals per 90

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

0.12 this player0.03 defender median91st 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
€300k
Mar 2024
Peak
€25M
Mar 2026
Model target
€25M
Jun 2026
Valuations
8
2 club changes
Jun 2026€25MChelsea FCValuation the model is trained to reproduce

Jun 2026: €25M, Chelsea FC. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2024-03-14€300kChelsea FC U18
2024-12-16€1MChelsea FC U21
2025-03-18€5MChelsea FC
2025-05-30€8MChelsea FC
2025-10-17€15MChelsea FC
2025-12-09€20MChelsea FC
2026-03-09€25MChelsea FC
2026-06-03€25MChelsea 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
+0.105

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 →

Premier League555 players · median €18M

Valued above 63% of the 555 Premier League players.

€150k€1M€7.5M€50M€25MSee them in the Explorer →

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

Valued above 93% of the 2,065 defenders.

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

Where Acheampong 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).