FairValue

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Portrait of Jack Stephens

Jack

Stephens

CBEngland · Southampton FC

№ 163744Emerging €1.6M −0.28

Image: FootyLogos

Player dossierPremier League

JackStephens

CBCentre-BackDefender

Club
Southampton FC
League
Premier League
Nationality
England
Age
31
Height
185 cm
Foot
Right
Valued
3 Dec 2025

Reading the valuation

The market values Stephens at €1.2M. Model A, which never saw Stephens during training, estimates €1.6M: the market value is 25% below that estimate.

That is a factor of ×1.33. 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 €445k, 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.

▼ −0.28A €1.6M▲ +0.99B €445k
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
19
Minutes
1,394
Goals
1
Assists
0
Started
17/19
Min / app
73
Cards
2Y 2R

Club matches, two years to the valuation date

The Valuation Journey

What moves Model A

Asking the prediction API to explain Model A for Stephens…

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 €1.2M

Checking API
EmergingEstablishedEliteWorld Class€2M€10M€30M€100k€1M€100MMarket €1.2MModel A €1.6M

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

Jack Stephens's percentiles among defenders: Goals per 90 72nd, Assists per 90 17th, Minutes, two years 21st, Starts 68th, Minutes, last 365 days 16th, European club minutes 30th72ndGoals17thAssists21stMinutes68thStarts16thRecent30thEurope

Dashed ring: the defender median (50th percentile)

Goals per 90

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

0.06 this player0.03 defender median72nd 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
€50k
Nov 2010
Peak
€8M
Mar 2018
Model target
€1.2M
Dec 2025
Valuations
32
8 club changes
Dec 2025€1.2MSouthampton FCValuation the model is trained to reproduce

Dec 2025: €1.2M, Southampton FC. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2010-11-26€50kPlymouth Argyle
2011-04-07€125kSouthampton FC Reserves
2013-07-25€150kSouthampton FC
2015-02-27€250kSwindon Town
2015-09-24€250kMiddlesbrough FC
2016-05-30€250kCoventry City
2016-08-01€250kSouthampton FC
2017-02-20€750kSouthampton FC
2017-06-28€3.5MSouthampton FC
2017-10-23€5MSouthampton FC
2018-01-02€5MSouthampton FC
2018-03-23€8MSouthampton FC
2018-05-28€8MSouthampton FC
2018-12-19€8MSouthampton FC
2019-06-13€8MSouthampton FC
2019-12-10€7MSouthampton FC
2020-04-08€5.5MSouthampton FC
2020-10-13€5.5MSouthampton FC
2021-03-18€4.5MSouthampton FC
2021-06-08€5MSouthampton FC
2021-10-05€8MSouthampton FC
2021-12-23€8MSouthampton FC
2022-06-15€7MSouthampton FC
2022-11-03€5MAFC Bournemouth
2023-06-20€3.5MSouthampton FC
2023-10-27€3MSouthampton FC
2023-12-21€2.5MSouthampton FC
2024-03-07€2.2MSouthampton FC
2024-05-24€2MSouthampton FC
2024-12-16€2MSouthampton FC
2025-05-30€1.5MSouthampton FC
2025-12-03€1.2MSouthampton FC

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
−0.285

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 →

Premier League555 players · median €18M

Valued above 6% of the 555 Premier League players.

€150k€1M€7.5M€50M€1.2MSee them in the Explorer →

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

Valued above 39% of the 2,065 defenders.

€20k€200k€2M€20M€1.2MSee them in the Explorer →

Where Stephens 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).