FairValue

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Portrait of Diogo Costa

Diogo

Costa

GKPortugal · FC Porto

№ 357153World Class €27.8M +0.36

Photo: Bryan Berlin / WikiPortraits, CC BY-SA 4.0 (background removed)

Player dossierLiga Portugal

DiogoCosta

GKGoalkeeperGoalkeeper

Club
FC Porto
League
Liga Portugal
Nationality
Portugal
Age
26
Height
188 cm
Foot
Right
Valued
28 May 2026

Reading the valuation

The market values Costa at €40M. Model A, which never saw Costa during training, estimates €27.8M: the market value is 44% above that estimate.

That is a factor of ×1.44. 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 €25.4M, 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.

▲ +0.36A €27.8M▲ +0.45B €25.4M
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
88
Minutes
7,887
Started
88/88
Min / app
90
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 Costa…

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 €40M

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €40MModel A €27.8M

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 485 goalkeepers

Diogo Costa's percentiles among goalkeepers: Minutes, two years 97th, Starts 62nd, Minutes, last 365 days 95th, European club minutes 90th97thMinutes62ndStarts95thRecent90thEurope

Dashed ring: the goalkeeper median (50th percentile)

Minutes, two years

Total club minutes in the two-year window: how much the player was used.

7,887 this player2,790 goalkeeper median97th percentile

450peer deciles · median line · this player ●9,210

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
€25k
Sept 2016
Peak
€45M
Mar 2023
Model target
€40M
May 2026
Valuations
26
1 club change
May 2026€40MFC PortoValuation the model is trained to reproduce

May 2026: €40M, FC Porto. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2016-09-30€25kFC Porto B
2017-06-30€100kFC Porto B
2017-09-08€500kFC Porto B
2018-02-23€1MFC Porto B
2018-06-29€2MFC Porto B
2019-02-12€3MFC Porto B
2019-06-07€4MFC Porto B
2019-12-30€5MFC Porto
2020-04-08€4.5MFC Porto
2020-08-17€5MFC Porto
2021-01-28€6MFC Porto
2021-05-21€6MFC Porto
2021-09-21€10MFC Porto
2021-12-27€16MFC Porto
2022-05-31€25MFC Porto
2022-11-01€35MFC Porto
2023-03-02€45MFC Porto
2023-06-16€45MFC Porto
2023-12-27€45MFC Porto
2024-06-06€40MFC Porto
2024-07-18€45MFC Porto
2024-12-19€40MFC Porto
2025-03-31€38MFC Porto
2025-05-30€40MFC Porto
2025-12-18€40MFC Porto
2026-05-28€40MFC Porto

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
+0.365

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

Joint 6th highest observed value among 423 Liga Portugal players.

€20k€200k€2M€20M€40MSee them in the Explorer →

Goalkeepers, all leagues485 players · median €1M

Joint 3rd highest observed value among 485 goalkeepers.

€20k€200k€2M€20M€40MSee them in the Explorer →

Where Costa 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).