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…

Issiaga

Sylla

LBGuinea · Asteras Aktor

№ 220878Emerging €271k +0.95

Player dossierSuper League

IssiagaSylla

LBLeft-BackDefender

Club
Asteras Aktor
League
Super League
Nationality
Guinea
Age
32
Height
180 cm
Foot
Left
Valued
4 Jun 2026

Reading the valuation

The market values Sylla at €700k. Model A, which never saw Sylla during training, estimates €271k: the market value is 159% above that estimate.

That is a factor of ×2.59. 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 €372k, 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.

▲ +0.95A €271k▲ +0.63B €372k
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
38
Minutes
2,676
Goals
1
Assists
0
Started
32/38
Min / app
70
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 Sylla…

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 €700k

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €700kModel A €271k

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

Issiaga Sylla's percentiles among defenders: Goals per 90 52nd, Assists per 90 17th, Minutes, two years 46th, Starts 54th, Minutes, last 365 days 46th, European club minutes 30th52ndGoals17thAssists46thMinutes54thStarts46thRecent30thEurope

Dashed ring: the defender median (50th percentile)

Starts

Share of appearances started rather than entered from the bench.

84% this player83% defender median54th 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
€250k
Mar 2013
Peak
€3.5M
Jun 2019
Model target
€700k
Jun 2026
Valuations
32
6 club changes
Jun 2026€700kAsteras AktorValuation the model is trained to reproduce

Jun 2026: €700k, Asteras Aktor. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2013-03-07€250kFC Toulouse
2013-05-30€600kFC Toulouse
2013-09-13€1MFC Toulouse
2014-01-14€2MFC Toulouse
2014-08-07€3MFC Toulouse
2015-01-14€2.5MFC Toulouse
2015-06-06€1.5MFC Toulouse
2016-02-04€2MGFC Ajaccio
2016-07-13€2MFC Toulouse
2017-01-16€3MFC Toulouse
2017-06-01€3MFC Toulouse
2018-01-24€3MFC Toulouse
2018-06-04€3MFC Toulouse
2018-12-17€3MFC Toulouse
2019-06-03€3.5MFC Toulouse
2019-12-19€3.5MFC Toulouse
2020-04-08€2.8MFC Toulouse
2020-10-15€2.5MRC Lens
2021-01-07€3MRC Lens
2021-06-04€2MRC Lens
2021-12-27€2MFC Toulouse
2022-06-02€1.8MFC Toulouse
2022-11-02€2MFC Toulouse
2023-06-27€2.5MMontpellier HSC
2023-12-18€2.5MMontpellier HSC
2024-06-03€2.5MMontpellier HSC
2024-12-10€2MMontpellier HSC
2025-06-03€1.5MMontpellier HSC
2025-09-23€1.2MAsteras Aktor
2025-12-12€900kAsteras Aktor
2026-03-06€800kAsteras Aktor
2026-06-04€700kAsteras Aktor

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
+0.950

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 →

Super League356 players · median €600k

Valued above 55% of the 356 Super League players.

€20k€150k€1M€7.5M€700kSee them in the Explorer →

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

Valued above 26% of the 2,065 defenders.

€20k€200k€2M€20M€700kSee them in the Explorer →

Where Sylla 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).