The problem
A similar player is not automatically a suitable replacement. I wanted to make football recruitment questions inspectable: which observed characteristics matter, what does the available data actually cover, and how sensitive is a comparison to the chosen requirements?
The approach
I combined a reproducible Python research pipeline with a Next.js and TypeScript interface. StatsBomb and Pappalardo-Wyscout observations retain their source definitions and coverage labels. The product connects searchable player-season profiles, role-based Player DNA, explicit recruitment requirements, club context and shareable comparison scenarios.
The challenge
Football datasets differ in definitions, seasons and coverage. Apparent similarity can reflect the data source or a small comparison pool. I therefore kept metadata separate from performance observations, compared models with simple baselines and made unsupported comparisons and uncertainty visible in the product.
From player search to a research question
Version 1.2 includes 3,739 observed player-season profiles across 18 competition families. These are historical, provider-scoped observations, not a count of unique players or a current transfer database. Recruitment exploration covers men's Big Five club-seasons alongside a Women's Super League mode.
- Search player profiles and inspect source coverage before comparing performance.
- Compare observed Player DNA, set requirements and inspect why candidates match or differ.
- Explore club context and test how changing weights or profiles affects a shortlist.
Outcome & value
A live English/Dutch research product with public source code, documented methods and reproducible release checks. The evaluation did not support broad cross-league translation or establish improved transfer decisions. Rankings describe observed similarity under selected criteria; they are not transfer recommendations or predictions of success.
Lessons learned
A useful data product must explain where a comparison stops being reliable. Source provenance, simple baselines and negative findings belong in the interface as well as the research documentation.
Evidence & artifacts
- WEBOpen Football Recruitment Intelligence
Live research platform on Render, with an English/Dutch language switch.
- CODEMethods, evaluation and data sources
Research documentation, model limitations and links to the original data providers.
- CODE
