FairValue

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

Costas

CBSpain · Real Oviedo

№ 276111Emerging €1.3M −0.10

Player dossierLaLiga

DavidCostas

CBCentre-BackDefender

Club
Real Oviedo
League
LaLiga
Nationality
Spain
Age
31
Height
184 cm
Foot
Right
Valued
5 Jun 2026

Reading the valuation

The market values Costas at €1.2M. Model A, which never saw Costas during training, estimates €1.3M: the market value is 9% below that estimate.

That is a factor of ×1.10. 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 €1M, 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 €1.3M▲ +0.18B €1M
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
25
Minutes
2,064
Goals
1
Assists
0
Started
22/25
Min / app
83
Cards
3Y 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 Costas…

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 €1.2M

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €1.2MModel A €1.3M

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

David Costas's percentiles among defenders: Goals per 90 59th, Assists per 90 17th, Minutes, two years 35th, Starts 63rd, Minutes, last 365 days 64th, European club minutes 30th59thGoals17thAssists35thMinutes63rdStarts64thRecent30thEurope

Dashed ring: the defender median (50th percentile)

Minutes, last 365 days

Club minutes in the final year of the window: recent involvement, or the absence of it.

2,064 this player1,687 defender median64th percentile

0peer deciles · median line · this player ●4,941

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
€400k
Oct 2013
Peak
€3.5M
Jan 2018
Model target
€1.2M
Jun 2026
Valuations
29
8 club changes
Jun 2026€1.2MReal OviedoValuation the model is trained to reproduce

Jun 2026: €1.2M, Real Oviedo. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2013-10-18€400kCelta de Vigo
2014-01-23€1.2MCelta de Vigo
2014-07-20€1.5MCelta de Vigo
2015-01-23€1MCelta de Vigo
2015-07-01€1MCelta de Vigo
2016-02-22€1MRCD Mallorca
2016-07-15€1MCelta de Vigo
2017-01-24€800kReal Oviedo
2017-06-29€1MReal Oviedo
2018-01-01€3.5MFC Barcelona B
2018-05-30€3.5MFC Barcelona B
2018-12-21€3MCelta de Vigo
2019-06-11€3MCelta de Vigo
2019-12-20€2MCelta de Vigo
2020-04-08€1.6MUD Almería
2020-10-08€1.6MCelta de Vigo
2021-01-05€1.2MCelta de Vigo
2021-06-10€1.2MCelta de Vigo
2021-12-27€1.5MReal Oviedo
2022-06-29€1.5MReal Oviedo
2022-09-26€1.2MReal Oviedo
2022-12-29€1.5MReal Oviedo
2023-06-14€1.5MReal Oviedo
2023-12-20€1.5MReal Oviedo
2024-06-24€1.4MReal Oviedo
2024-12-13€1.4MReal Oviedo
2025-06-24€1.4MReal Oviedo
2025-12-12€1.4MReal Oviedo
2026-06-05€1.2MReal Oviedo

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
−0.098

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 →

LaLiga509 players · median €4M

Valued above 15% of the 509 LaLiga players.

€100k€1M€10M€100M€1.2MSee them in the Explorer →

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

Valued above 39% of the 2,065 defenders.

€20k€200k€2M€20M€1.2MSee them in the Explorer →

Where Costas 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).