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…

Portrait of Gabriel Martinelli

Gabriel

Martinelli

LWBrazil · Arsenal FC

№ 655488World Class €65.5M −0.38

Image: FootyLogos

Player dossierPremier League

GabrielMartinelli

LWLeft WingerAttack

Club
Arsenal FC
League
Premier League
Nationality
Brazil
Age
24
Height
178 cm
Foot
Right
Valued
3 Jun 2026

Reading the valuation

The market values Martinelli at €45M. Model A, which never saw Martinelli during training, estimates €65.5M: the market value is 31% below that estimate.

That is a factor of ×1.45. 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 €57.6M, 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.

▼ −0.38A €65.5M▼ −0.25B €57.6M
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
99
Minutes
5,703
Goals
21
Assists
13
Started
62/99
Min / app
58
Cards
8Y 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 Martinelli…

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 €45M

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €45MModel A €65.5M

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 1,583 attackers

Gabriel Martinelli's percentiles among attackers: Goals per 90 63rd, Assists per 90 71st, Minutes, two years 96th, Starts 56th, Minutes, last 365 days 83rd, European club minutes 93rd63rdGoals71stAssists96thMinutes56thStarts83rdRecent93rdEurope

Dashed ring: the attacker median (50th percentile)

Minutes, two years

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

5,703 this player2,242 attacker median96th percentile

450peer deciles · median line · this player ●8,788

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
€5M
Aug 2019
Peak
€85M
Dec 2023
Model target
€45M
Jun 2026
Valuations
23
0 club changes
Jun 2026€45MArsenal FCValuation the model is trained to reproduce

Jun 2026: €45M, Arsenal FC. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2019-08-07€5MArsenal FC
2019-09-12€8MArsenal FC
2019-12-10€18MArsenal FC
2020-03-09€28MArsenal FC
2020-04-08€25MArsenal FC
2020-10-13€25MArsenal FC
2021-03-18€22MArsenal FC
2021-06-08€22MArsenal FC
2021-12-23€28MArsenal FC
2022-03-29€38MArsenal FC
2022-06-15€40MArsenal FC
2022-11-03€60MArsenal FC
2023-03-16€70MArsenal FC
2023-06-20€80MArsenal FC
2023-12-19€85MArsenal FC
2024-03-14€80MArsenal FC
2024-05-27€70MArsenal FC
2024-10-01€60MArsenal FC
2024-12-16€55MArsenal FC
2025-05-30€55MArsenal FC
2025-10-17€45MArsenal FC
2025-12-09€45MArsenal FC
2026-06-03€45MArsenal FC

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
−0.375

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 86% of the 555 Premier League players.

€150k€1M€7.5M€50M€45MSee them in the Explorer →

Attackers, all leagues1,583 players · median €2.5M

Valued above 96% of the 1,583 attackers.

€20k€300k€5M€75M€45MSee them in the Explorer →

Where Martinelli 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).