What statistical data of observational performance can tell us and what they cannot: the case ofDutee Chand v. AFI & IAAF

How can performance data resolve the arbitration of sensitive matters in the world of sports? In the absence of experimental data (ie, clinical trials), researchers must build an argument based on correlations in observational data. Such data are often not widely available. The Dutee Chand v. AFI & IAAF case is a case in point (box 1).1 Box ### Background on the  Dutee Chand v. AFI & IAAF case IAAF Hyperandrogenism Regulations were in place from 1 May 2011 to 24 July 2015 when they were suspended by the Court of Arbitration for Sport (CAS). The regulations stated that female athletes who naturally produce levels of testosterone >10 nmol/L were not eligible to compete in the female category and need to take androgen-suppressive drugs to resume competition. Dutee Chand, an Indian sprinter, was asked to abide by these regulations in July 2014 and appealed to CAS on grounds that the regulations unfairly discriminated against women who naturally produced higher levels of testosterone. CAS was not satisfied with the evidence IAAF provided and hence suspended the regulations on 24 July 2015, but allowed the International Association of Athletics Federations (IAAF) up to 2 years (later extended) to submit additional evidence on the correlation between endogenous levels of testosterone and athletic performance. The regulations currently remain suspended until 19 July …