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…

Rubén

Peña

RBSpain · CD Leganés

№ 238868Emerging €318k +0.64

Player dossierLaLiga

RubénPeña

RBRight-BackDefender

Club
CD Leganés
League
LaLiga
Nationality
Spain
Age
34
Height
170 cm
Foot
Right
Valued
30 Dec 2025

Reading the valuation

The market values Peña at €600k. Model A, which never saw Peña during training, estimates €318k: the market value is 89% above that estimate.

That is a factor of ×1.89. Model A's typical held-out miss is ×1.50 either way, so this gap is larger than its usual error.

Without league and club, Model B estimates €144k, 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.

▲ +0.64A €318k▲ +1.42B €144k
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
45
Minutes
2,075
Goals
0
Assists
1
Started
23/45
Min / app
46
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 Peña…

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 €600k

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €600kModel A €318k

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

Rubén Peña's percentiles among defenders: Goals per 90 18th, Assists per 90 52nd, Minutes, two years 35th, Starts 9th, Minutes, last 365 days 9th, European club minutes 30th18thGoals52ndAssists35thMinutes9thStarts9thRecent30thEurope

Dashed ring: the defender median (50th percentile)

Assists per 90

Club assists per 90 minutes in the same window.

0.04 this player0.04 defender median52nd 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
€200k
Jan 2013
Peak
€10M
Feb 2019
Model target
€600k
Dec 2025
Valuations
32
5 club changes
Dec 2025€600kCD LeganésValuation the model is trained to reproduce

Dec 2025: €600k, CD Leganés. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2013-01-11€200kReal Valladolid B
2013-06-14€200kReal Valladolid B
2014-08-13€400kCD Leganés
2015-01-08€400kCD Leganés
2015-07-01€400kCD Leganés
2016-02-22€400kCD Leganés
2016-07-15€800kSD Eibar
2017-01-24€800kSD Eibar
2017-03-29€1.5MSD Eibar
2017-06-05€1.5MSD Eibar
2018-01-01€1MSD Eibar
2018-03-22€1.5MSD Eibar
2018-05-30€2MSD Eibar
2018-12-21€7.5MSD Eibar
2019-02-28€10MSD Eibar
2019-06-11€10MSD Eibar
2019-09-10€8MVillarreal CF
2019-12-20€8MVillarreal CF
2020-04-08€6.5MVillarreal CF
2020-10-08€6MVillarreal CF
2021-01-05€4MVillarreal CF
2021-06-10€4MVillarreal CF
2021-12-30€3MVillarreal CF
2022-06-03€2.5MVillarreal CF
2022-11-07€2.5MCA Osasuna
2023-06-13€2.5MCA Osasuna
2023-12-22€2.5MCA Osasuna
2024-06-07€2.2MCA Osasuna
2024-12-27€1.8MCA Osasuna
2025-06-09€1.2MCA Osasuna
2025-10-16€700kCD Leganés
2025-12-30€600kCD Leganés

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
+0.636

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 3% of the 509 LaLiga players.

€100k€1M€10M€100M€600kSee them in the Explorer →

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

Valued above 22% of the 2,065 defenders.

€20k€200k€2M€20M€600kSee them in the Explorer →

Where Peña 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).