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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Junior

Diaz

CBCote d'Ivoire · Stade Brestois 29

№ 1009596Established €5.1M +0.16

Player dossierLigue 1

JuniorDiaz

CBCentre-BackDefender

Club
Stade Brestois 29
League
Ligue 1
Nationality
Cote d'Ivoire
Age
22
Height
193 cm
Foot
Right
Valued
1 Jun 2026

Reading the valuation

The market values Diaz at €6M. Model A, which never saw Diaz during training, estimates €5.1M: the market value is 18% above 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 €1.9M, 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.

▲ +0.16A €5.1M▲ +1.13B €1.9M
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
20
Minutes
1,560
Goals
0
Assists
1
Started
17/20
Min / app
78
Cards
4Y 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 Diaz…

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 €6M

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €6MModel A €5.1M

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

Junior Diaz's percentiles among defenders: Goals per 90 18th, Assists per 90 62nd, Minutes, two years 24th, Starts 56th, Minutes, last 365 days 47th, European club minutes 30th18thGoals62ndAssists24thMinutes56thStarts47thRecent30thEurope

Dashed ring: the defender median (50th percentile)

Assists per 90

Club assists per 90 minutes in the same window.

0.06 this player0.04 defender median62nd percentile

0.00peer deciles · median line · this player ●0.58

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
€100k
Sept 2022
Peak
€6M
Mar 2026
Model target
€6M
Jun 2026
Valuations
13
3 club changes
Jun 2026€6MStade Brestois 29Valuation the model is trained to reproduce

Jun 2026: €6M, Stade Brestois 29. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2022-09-19€100kFC Nantes B
2022-11-02€100kFC Nantes B
2023-06-27€100kFC Nantes B
2023-12-13€400kFC Annecy
2024-06-11€400kFC Annecy
2024-10-03€1.5MESTAC Troyes
2024-12-04€2MESTAC Troyes
2025-03-12€3MESTAC Troyes
2025-06-02€4MESTAC Troyes
2025-10-10€5MStade Brestois 29
2025-12-15€5MStade Brestois 29
2026-03-27€6MStade Brestois 29
2026-06-01€6MStade Brestois 29

Audit context group-level, not about this player

Audit group
non-UEFA
Population gap, Model A
+0.093 95% CI +0.063 to +0.124
This player, market vs held-out A
+0.165

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 →

Ligue 1423 players · median €5M

Valued above 50% of the 423 Ligue 1 players.

€100k€750k€5M€30M€6MSee them in the Explorer →

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

Valued above 73% of the 2,065 defenders.

€20k€200k€2M€20M€6MSee them in the Explorer →

Where Diaz 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).