Relative Age Effects as Evidence of Selection Bias in Major League Baseball Draftees (2013–2018)

This study comprised 7,078 men drafted in the MLB first-year player draft from 2013 to 2018. Data collected for each draftee included birth date, year drafted, academic-level classification, position, round drafted, batting side, and throwing arm. Draftee's birth dates were categorized into quarters based on the calendar year for baseball in the United States (Q1: August–October; Q2: November–January; Q3: February–April; Q4: May–July). Player birth-date distributions were compared with average expected birth-date distributions and evaluated with the χ2 goodness of fit statistic. Significant χ2 tests were followed up by calculating the standardized residual for each quarter. Differences from the expected frequencies were found for the overall group (p
Source: Journal of Strength and Conditioning Research - Category: Sports Medicine Tags: Original Research Source Type: research