In collaboration with Professor Adam L. Kelly and the BCU RAYSD Lab, the KNVB’s “Relative Age Solutions Project” tackles the well-documented geboortemaandeffect—where children born earlier in the more likely selected in youth football—by moving from awareness to action through a structured, three-part research initiative.
Part One: A Call to Action
In April 2025, Professor Adam L. Kelly, Jan Verbeek, and colleagues published a study inviting stakeholders—including coaches, academics, parents, and policy-makers—to submit solutions via an open questionnaire. After sifting through 185 submissions, they identified 143 unique proposals. These were sorted into three broad themes: (1) altering observers’ behaviour (e.g., increasing coach awareness), (2) implementing selection rules (e.g., entry exemptions), and (3) restructuring competitions (e.g., modifying age bands). While no novel strategies beyond those in existing literature emerged, only two—'cueing age differences’ and ‘grouping by chronological and biological age’—had been empirically tested in football.
Part Two: Delphi Consensus on Solutions
In May 2025, the project progressed to an adapted e-Delphi study involving 15 international experts. Each of the 13 proposed lower-order strategies was rated on both effectiveness against relative ages effects and feasibility of implementation. ‘Rotating cut-off dates’ scored highest for direct effectiveness (mean 6.2/9) but was considered less feasible (4.6/9), while ‘cueing differences in age’—making a player’s birth month explicitly visible to coaches—garnered the highest overall viability score (5.8/9), balancing both impact and practicality. Notably, the experts did not reach consensus on many solutions, underscoring the complexity of choosing the right interventions for the right environment.
Part Three: From Knowledge to Action – Next Steps and Implications
The BCU RAYSD Lab and the KNVB now plans to pilot the most promising interventions—using a hybrid approach—with rigorous evaluation in real-world youth football. Their long‑term vision is to transition from awareness and proposal stages to tested policy changes that reduce age bias and improve fairness. This project represents a rare, methodical approach to solving or moderating relative age effects in football, moving from theory to practice in Dutch youth football.