FairValue

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  • EnvironmentOverviewWhat FairValue measures, what it found, where to go next.
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Portrait of Georgios Vagiannidis

Georgios

Vagiannidis

RBGreece · Sporting CP

№ 546186Established €8.1M −0.01

Image: FootyLogos

Player dossierLiga Portugal

GeorgiosVagiannidis

RBRight-BackDefender

Club
Sporting CP
League
Liga Portugal
Nationality
Greece
Age
24
Height
182 cm
Foot
Right
Valued
28 May 2026

Reading the valuation

The market values Vagiannidis at €8M. Model A, which never saw Vagiannidis during training, estimates €8.1M: the market value is 1% below that estimate.

That is a factor of ×1.01. 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 €4.6M, 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.

▼ −0.01A €8.1M▲ +0.56B €4.6M
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
55
Minutes
3,590
Goals
1
Assists
7
Started
37/55
Min / app
65
Cards
10Y 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 Vagiannidis…

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 €8M

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €8MModel A €8.1M

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

Georgios Vagiannidis's percentiles among defenders: Goals per 90 44th, Assists per 90 92nd, Minutes, two years 63rd, Starts 24th, Minutes, last 365 days 48th, European club minutes 74th44thGoals92ndAssists63rdMinutes24thStarts48thRecent74thEurope

Dashed ring: the defender median (50th percentile)

Assists per 90

Club assists per 90 minutes in the same window.

0.18 this player0.04 defender median92nd 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
€400k
Aug 2020
Peak
€12M
Sept 2025
Model target
€8M
May 2026
Valuations
20
4 club changes
May 2026€8MSporting CPValuation the model is trained to reproduce

May 2026: €8M, Sporting CP. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2020-08-04€400kPanathinaikos
2020-10-16€400kSint-Truidense VV
2021-03-17€250kSint-Truidense VV
2021-06-07€200kSint-Truidense VV
2021-12-28€250kPanathinaikos B
2022-06-27€250kPanathinaikos B
2022-11-07€300kPanathinaikos
2023-02-27€500kPanathinaikos
2023-05-22€1.2MPanathinaikos
2023-09-21€1.8MPanathinaikos
2023-12-20€2.2MPanathinaikos
2024-03-06€4MPanathinaikos
2024-05-30€4MPanathinaikos
2024-09-26€5MPanathinaikos
2024-12-18€6MPanathinaikos
2025-03-14€7MPanathinaikos
2025-05-23€8MPanathinaikos
2025-09-30€12MSporting CP
2025-12-18€11MSporting CP
2026-05-28€8MSporting CP

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
−0.008

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 84% of the 423 Liga Portugal players.

€20k€200k€2M€20M€8MSee them in the Explorer →

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

Valued above 78% of the 2,065 defenders.

€20k€200k€2M€20M€8MSee them in the Explorer →

Where Vagiannidis 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).