FairValue

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

Mancha

CBBrazil · Rio Ave FC

№ 1082582Emerging €1.8M −0.19

Player dossierLiga Portugal

GustavoMancha

CBCentre-BackDefender

Club
Rio Ave FC
League
Liga Portugal
Nationality
Brazil
Age
21
Height
190 cm
Foot
Left
Valued
28 May 2026

Reading the valuation

The market values Mancha at €1.5M. Model A, which never saw Mancha during training, estimates €1.8M: the market value is 17% below that estimate.

That is a factor of ×1.21. 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 €1.7M, 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.

▼ −0.19A €1.8M▼ −0.11B €1.7M
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
22
Minutes
1,963
Goals
0
Assists
0
Started
22/22
Min / app
89
Cards
6Y 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 Mancha…

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 €1.5M

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €1.5MModel A €1.8M

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

Gustavo Mancha's percentiles among defenders: Goals per 90 18th, Assists per 90 17th, Minutes, two years 33rd, Starts 97th, Minutes, last 365 days 60th, European club minutes 30th18thGoals17thAssists33rdMinutes97thStarts60thRecent30thEurope

Dashed ring: the defender median (50th percentile)

Starts

Share of appearances started rather than entered from the bench.

100% this player83% defender median97th percentile

18%peer deciles · median line · this player ●100%

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
€700k
Jun 2025
Peak
€1.5M
May 2026
Model target
€1.5M
May 2026
Valuations
4
2 club changes
May 2026€1.5MRio Ave FCValuation the model is trained to reproduce

May 2026: €1.5M, Rio Ave FC. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2025-06-06€700kFortaleza Esporte Clube
2025-09-23€1MOlympiacos Piraeus
2025-12-12€1MOlympiacos Piraeus
2026-05-28€1.5MRio Ave 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
−0.189

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 →

Liga Portugal423 players · median €1M

Valued above 53% of the 423 Liga Portugal players.

€20k€200k€2M€20M€1.5MSee them in the Explorer →

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

Valued above 43% of the 2,065 defenders.

€20k€200k€2M€20M€1.5MSee them in the Explorer →

Where Mancha 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).