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…

Phillip

Tietz

CFGermany · 1.FSV Mainz 05

№ 288340Established €5.9M −0.38

Player dossierBundesliga

PhillipTietz

CFCentre-ForwardAttack

Club
1.FSV Mainz 05
League
Bundesliga
Nationality
Germany
Age
28
Height
190 cm
Foot
Right
Valued
27 May 2026

Reading the valuation

The market values Tietz at €4M. Model A, which never saw Tietz during training, estimates €5.9M: the market value is 32% below that estimate.

That is a factor of ×1.46. 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 €3.2M, 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.

▼ −0.38A €5.9M▲ +0.21B €3.2M
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
69
Minutes
3,996
Goals
14
Assists
7
Started
44/69
Min / app
58
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 Tietz…

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 €5.9M

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 1,583 attackers

Phillip Tietz's percentiles among attackers: Goals per 90 59th, Assists per 90 54th, Minutes, two years 81st, Starts 58th, Minutes, last 365 days 71st, European club minutes 28th59thGoals54thAssists81stMinutes58thStarts71stRecent28thEurope

Dashed ring: the attacker median (50th percentile)

Minutes, two years

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

3,996 this player2,242 attacker median81st percentile

450peer deciles · median line · this player ●8,788

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
€150k
Feb 2016
Peak
€5M
Mar 2024
Model target
€4M
May 2026
Valuations
27
7 club changes
May 2026€4M1.FSV Mainz 05Valuation the model is trained to reproduce

May 2026: €4M, 1.FSV Mainz 05. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table
DateMarket valueClub
2016-02-27€150kEintracht Braunschweig U19
2016-03-22€300kEintracht Braunschweig U19
2016-07-22€300kEintracht Braunschweig
2017-01-23€300kEintracht Braunschweig
2017-06-27€250kEintracht Braunschweig
2018-01-19€250kSC Paderborn 07
2018-06-08€350kSC Paderborn 07
2019-01-15€350kFC Carl Zeiss Jena
2019-06-14€350kFC Carl Zeiss Jena
2019-12-13€350kSV Wehen Wiesbaden
2020-04-08€300kSV Wehen Wiesbaden
2021-01-20€300kSV Wehen Wiesbaden
2021-06-14€400kSV Wehen Wiesbaden
2021-10-13€900kSV Darmstadt 98
2021-12-15€1.7MSV Darmstadt 98
2022-06-16€2MSV Darmstadt 98
2022-09-28€2.5MSV Darmstadt 98
2022-11-30€2.5MSV Darmstadt 98
2023-06-28€2.7MSV Darmstadt 98
2023-10-18€3MFC Augsburg
2023-12-14€4MFC Augsburg
2024-03-27€5MFC Augsburg
2024-05-29€5MFC Augsburg
2024-12-20€5MFC Augsburg
2025-06-05€5MFC Augsburg
2025-12-19€3.5MFC Augsburg
2026-05-27€4M1.FSV Mainz 05

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
−0.380

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 →

Bundesliga451 players · median €5M

Valued above 39% of the 451 Bundesliga players.

€300k€2M€15M€100M€4MSee them in the Explorer →

Attackers, all leagues1,583 players · median €2.5M

Valued above 59% of the 1,583 attackers.

€20k€300k€5M€75M€4MSee them in the Explorer →

Where Tietz 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).