To the Editor: As Bilimoria et al. (Feb. 25 issue) note in their article on the Flexibility in Duty Hour Requirements for Surgical Trainees (FIRST) Trial, the 2011 duty-hour reforms of the Accreditation Council for Graduate Medical Education (ACGME) created controversy in the medical community. Several groups have questioned the benefits of these reforms. Important to the controversy is underreporting of duty hours by residents. Underreporting may be a significant source of bias in studies of ACGME duty-hour reforms.