FairValue

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  • EnvironmentOverviewWhat FairValue measures, what it found, where to go next.
  • EnvironmentTerminalExplore, compare and track players; market, league and model views.
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  • TerminalMarket LandscapeHow observed value is distributed, and where the model drifts.

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Lance

Duijvestijn

AMNetherlands · Fortuna Sittard

№ 378316Emerging €1.1M −0.33

Player dossierEredivisie

LanceDuijvestijn

AMAttacking MidfieldMidfield

Club
Fortuna Sittard
League
Eredivisie
Nationality
Netherlands
Age
27
Height
190 cm
Foot
Right
Valued
28 May 2026

Reading the valuation

The market values Duijvestijn at €800k. Model A, which never saw Duijvestijn during training, estimates €1.1M: the market value is 28% below that estimate.

That is a factor of ×1.39. 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 €1.4M, 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.

▼ −0.33A €1.1M▼ −0.58B €1.4M
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
30
Minutes
2,051
Goals
4
Assists
3
Started
22/30
Min / app
68
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 Duijvestijn…

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 €800k

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €800kModel A €1.1M

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 1,687 midfielders

Lance Duijvestijn's percentiles among midfielders: Goals per 90 78th, Assists per 90 65th, Minutes, two years 38th, Starts 58th, Minutes, last 365 days 66th, European club minutes 30th78thGoals65thAssists38thMinutes58thStarts66thRecent30thEurope

Dashed ring: the midfielder median (50th percentile)

Goals per 90

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

0.18 this player0.08 midfielder median78th percentile

0.00peer deciles · median line · this player ●0.93

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
Jan 2019
Peak
€850k
Jun 2025
Model target
€800k
May 2026
Valuations
17
5 club changes
May 2026€800kFortuna SittardValuation the model is trained to reproduce

May 2026: €800k, Fortuna Sittard. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2019-01-21€25kNEC Nijmegen U21
2020-08-12€50kHelmond Sport
2020-10-24€125kHelmond Sport
2020-12-31€175kHelmond Sport
2021-03-16€225kHelmond Sport
2021-10-12€350kAlmere City FC
2022-01-12€425kAlmere City FC
2022-06-23€450kAlmere City FC
2023-04-03€500kAlmere City FC
2023-07-04€600kAlmere City FC
2023-12-15€500kAlmere City FC
2024-05-31€700kExcelsior Rotterdam
2024-12-10€600kExcelsior Rotterdam
2025-03-14€650kExcelsior Rotterdam
2025-06-09€850kExcelsior Rotterdam
2025-12-02€800kSparta Rotterdam
2026-05-28€800kFortuna Sittard

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
−0.330

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 →

Eredivisie425 players · median €1M

Valued above 40% of the 425 Eredivisie players.

€75k€500k€3M€20M€800kSee them in the Explorer →

Midfielders, all leagues1,687 players · median €2M

Valued above 27% of the 1,687 midfielders.

€20k€200k€2M€20M€800kSee them in the Explorer →

Where Duijvestijn 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).