How do Relative Age Effects in Junior Pathways change into the absence of RAEs in Senior Professional Cricket?

Highlights

RAE is carried over from junior pathways into (18+) professional cricket

RAE quickly declines through the Rookie phase (18-24)

RAE has reversed at the Prime phase (25-29)

If you measure the entire senior cohort of professional cricketers in England & Wales there is no overall Relative Age Effect, i.e. no Birth Quarter is dominant. However, we know that the development pathway, pre age18, produces more BQ1s and BQ2s than their later born peers. So does RAE magically disappear from age 19?

No, there is a gradual reset. Relatively more BQ1 & BQ2s enter as Rookies but by the time players reach their Prime at age 25, of those players more later born are still playing and more early born have left the professional game.

Using the players released/retired for the last two years (2021-2022) *, the first half of year (H1) versus the last half of year (H2) is thus:

U18-24 H1 70, H2 30 n=10

U25-29 H1 50, H2 50 n=14

30+ H1 57, H2 43 n=11

ALL H1 55, H2 45 n=35

An analysis of the 2020 county squads found the following age RAE profile breakdown:

U21 H1 64, H2 36 n=20

21-23 H1 54, H2 46 n=78

24-25 H1 49, H2 51 n=65

26-30 H1 46, H2 54 n=129

30+ H1 53, H2 48 n=119

How RAE affects a county career

A similar analysis, using three phases of Rookie, Prime and Veteran (Bryson, Gomez & Zhang, 2017) of the 2022 county squads found the following age RAE profile breakdown:

Rookie 19-24 H1 54, H2 46 n=173

Prime 25-30 H1 46, H2 54 n=119

Veteran 31-44 H1 53, H2 47 n=72

Discussion

A higher level of RAE in those released during the Rookie phase than that found in the Rookie phase is expected. This is how the RAE profile of the Prime phase becomes a Reverse RAE.

Conclusion

RAEs are carried over into professional cricket from junior cricket. They don’t disappear at the junior/senior transition point. It takes a further 5/6 years until early/late born parity is reached. Perhaps this is simply a ‘regression to the mean’ where overselected early born are slowly lost to the system and the underselected later born are retained at a relatively higher rate.

• Thanks to @DanKingdom96 for the list of released/retired players for 2021 and 2022.