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…

Rosen

Bozhinov

CBBulgaria · Pisa Sporting Club

№ 877124Established €5.2M −0.27

Player dossierSerie A

RosenBozhinov

CBCentre-BackDefender

Club
Pisa Sporting Club
League
Serie A
Nationality
Bulgaria
Age
21
Height
193 cm
Foot
Left
Valued
29 May 2026

Reading the valuation

The market values Bozhinov at €4M. Model A, which never saw Bozhinov during training, estimates €5.2M: the market value is 23% below that estimate.

That is a factor of ×1.30. 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 €5.1M, 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.

▼ −0.27A €5.2M▼ −0.24B €5.1M
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
32
Minutes
2,006
Goals
1
Assists
0
Started
24/32
Min / app
63
Cards
4Y 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 Bozhinov…

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 €4M

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €4MModel A €5.2M

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

Rosen Bozhinov's percentiles among defenders: Goals per 90 60th, Assists per 90 17th, Minutes, two years 34th, Starts 35th, Minutes, last 365 days 58th, European club minutes 30th60thGoals17thAssists34thMinutes35thStarts58thRecent30thEurope

Dashed ring: the defender median (50th percentile)

Goals per 90

Club goals per 90 minutes played in the two years to the valuation date.

0.04 this player0.03 defender median60th percentile

0.00peer deciles · median line · this player ●0.41

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
€10k
Apr 2022
Peak
€4M
Mar 2026
Model target
€4M
May 2026
Valuations
13
5 club changes
May 2026€4MPisa Sporting ClubValuation the model is trained to reproduce

May 2026: €4M, Pisa Sporting Club. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2022-04-30€10kCSKA-Sofia
2022-05-31€50kCSKA-Sofia
2022-11-28€50kCSKA 1948 III
2023-09-15€50kCSKA 1948 II
2023-12-20€50kCSKA 1948 II
2024-03-19€100kCSKA 1948
2024-06-03€200kCSKA 1948
2024-12-11€500kRoyal Antwerp FC
2025-06-12€400kRoyal Antwerp FC
2025-10-01€2.5MRoyal Antwerp FC
2025-12-10€2.5MRoyal Antwerp FC
2026-03-24€4MPisa Sporting Club
2026-05-29€4MPisa Sporting Club

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
−0.265

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 →

Serie A507 players · median €5.5M

Valued above 39% of the 507 Serie A players.

€100k€750k€5M€30M€4MSee them in the Explorer →

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

Valued above 65% of the 2,065 defenders.

€20k€200k€2M€20M€4MSee them in the Explorer →

Where Bozhinov 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).