Age-ordered shirt numbering fixes Relative Age Effect & Maturation Bias during trials

One of the ways to address the Relative Age Effect (RAE) found in cricket is to use age-ordered shirt numbering in trials.

Trials in cricket are ubiquitous. Often numbered bibs are used during trials to aid identification. A study by David Mann et al at PSV Eindhoven football club found that by putting these in age order, with the oldest #1 etc, this fairly simple and easy strategy reduced RAE.

I’ve not seen this in any trials, club, district, county, Bunbury (Regional U15s), Super Fours (Regional U17/18s). Does anyone use this in cricket?

What did the study find?

‘Talent scouts from an elite football club watched junior games and ranked players on the basis of their potential. Scouts were allocated to one of three groups provided with contrasting information about the age of the players: (1) no age information, (2) players’ birthdates or (3) knowledge that the numbers on the playing shirts corresponded to the relative age of the players.’

‘Results revealed a significant selection bias for the scouts in the no-age information group, and that bias remained when scouts knew the players’ dates-of-birth. Strikingly though, the selection bias was eliminated when scouts watched the games knowing the shirt numbers corresponded to the relative ages of the players.’

This could be more/most appropriate to the early stages of the pathway. The study was with U11 male footballers.

Study (2017)

UPDATE 25.4.2021:

Some as yet unpublished research repeated the age ordered shirts technique but with maturity rather than relative age and it worked equally well in countering coach evaluation biases. Dr. Sean Cumming, Department for Health, University of Bath.

UPDATE 15.12.2022

This research is now published.

Dennis Lüdin, Lars Donath, Stephen Cobley, David Mann & Michael Romann (2022) Player-labelling as a solution to overcome maturation selection biases in youth football, Journal of Sports Sciences, 40:14, 1641-1647, DOI: 10.1080/02640414.2022.2099077

Relative Age Effect and Maturation biases are two separate constructs.

Rob Reed
Rob Reed

Interested in Relative Age Effects & Maturation in Player Id & Development 🏏 #OneMoreSummer