DerickPoloni

LBLeft-BackDefender

Club: SC Farense
League: Liga Portugal
Nationality: Brazil
Age: 32
Height: 173 cm
Foot: Left
Valued: 22 Dec 2025

Reading the valuation

The market values Poloni at €150k. Model A, which never saw Poloni during training, estimates €352k: the market value is 57% below that estimate.

That is a factor of ×2.35. Model A's typical held-out miss is ×1.50 either way, so this gap is larger than its usual error.

Without league and club, Model B estimates €387k, 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.

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: 23
Minutes: 1,423
Goals: 1
Assists: 3
Started: 17/23
Min / app: 62
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 Poloni…

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 €150k

Checking API

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

Dashed ring: the defender median (50th percentile)

Assists per 90

Club assists per 90 minutes in the same window.

0.19 this player0.04 defender median94th 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: €100k; Sept 2017
Peak: €400k; Dec 2019
Model target: €150k; Dec 2025
Valuations: 18; 3 club changes

Dec 2025€150kSC FarenseValuation the model is trained to reproduce

Dec 2025: €150k, SC Farense. Dotted lines mark the €2M, €10M and €30M tier boundaries.

Show as a table

Date	Market value	Club
2017-09-08	€100k	Leixões SC
2018-02-23	€250k	Leixões SC
2018-06-29	€350k	Leixões SC
2019-02-12	€275k	Leixões SC
2019-06-29	€375k	Leixões SC
2019-12-31	€400k	Leixões SC
2020-04-08	€325k	Leixões SC
2020-11-02	€225k	Casa Pia AC
2021-06-29	€225k	Casa Pia AC
2022-04-01	€175k	Casa Pia AC
2022-06-27	€150k	Casa Pia AC
2022-11-01	€200k	Casa Pia AC
2023-06-16	€300k	Casa Pia AC
2023-12-20	€300k	CD Eldense
2024-06-24	€300k	CD Eldense
2024-12-19	€300k	SC Farense
2025-05-30	€300k	SC Farense
2025-12-22	€150k	SC Farense

Audit context group-level, not about this player

Audit group: non-UEFA
Population gap, Model A: +0.093 95% CI +0.063 to +0.124
This player, market vs held-out A: −0.854

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 4% of the 423 Liga Portugal players.

See them in the Explorer →

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

Valued above 3% of the 2,065 defenders.

See them in the Explorer →

Where Poloni appears

TerminalLiga Portugal in the Player Explorer
TerminalLiga Portugal on the League Landscape

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).