Birth date and birth place effects in National Hockey League draftees 2000–2005: comments on Baker and Logan (2007)
- University of Ottawa, Ontario, Canada
- Mr David J Hancock, 125 University Private, MNT 321, University of Offawa, Offawa, ON, Canada K1N 6NS; dhanc088{at}uottawa.ca
- Accepted 19 May 2008
Researchers who study the relative age effect (RAE) have stated that, within a given cohort, individuals who are relatively older tend to be over-represented at elite levels within sport. This RAE has been illustrated in hockey,1 soccer,2 and baseball,3 to name a few.
Recently, Baker and Logan4 conducted an analysis on the birth dates of players drafted to the National Hockey League (NHL) between 2000 and 2005. The results led them to conclude that a RAE existed, as relatively older players were over-represented in the NHL drafts. After appraising their contribution, we feel that there are three key points to be reconsidered. These considerations do not disqualify the notion that a RAE exists in NHL draftees; however, they compel one to re-examine study design issues and the interpretation of results.
QUARTILES AND SAMPLE
The first point for reconsideration concerns the birth quartiles used by the authors. Specifically, Baker and Logan4 divided their sample into quartiles (Q) based on the calendar year for US and Canadian hockey, which is 1 January to 31 December (Q1 = January to March, Q2 = April to June, Q3 = July to September, Q4 = October to December). The NHL draft calendar, however, runs from 16 September to 15 September. For example, in the 2008 NHL draft, first-year eligible players were born between 16 September 1989 and 15 September 1990. Thus, the relatively oldest players in an NHL draft cohort are born on …
