Design: Probability subsamples of AIS respondents, oversampling BIQ positives, completed short-term test-retest interviews (n = 59) or clinical reappraisal interviews (n = 203) to assess BIQ reliability and validity. Setting: The AIS is a large (n = 10,094) epidemiologic survey of the prevalence and correlates of insomnia. Participants: Adult subscribers to a national managed healthcare plan. Intervention: None Measurements and Results: BIQ test-retest correlations were 0.47-0.94 for nature of the sleep problems (initiation, maintenance, nonrestorative sleep [NRS]), 0.72-0.95 for problem frequency, 0.66-0.88 for daytime impairment/distress, and 0.62 for duration of sleep. Good individual-level concordance was found between BIQ diagnoses and diagnoses based on expert interviews for meeting hierarchy-free inclusion criteria for diagnoses in any of the diagnostic systems, with area under the receiver operating characteristic curve (AUC, a measure of classification accuracy insensitive to disorder prevalence) of 0.86 for dichotomous classifications. The AUC increased to 0.94 when symptom-level data were added to generate continuous predicted-probability of diagnosis measures. The AUC was lower for dichotomous classifications based on RDC/ICSD-2 (0.68) and ICD-10 (0.70) than for DSM-IV-TR (0.83) criteria but increased consistently when symptom-level data were added to generate continuous predicted-probability measures of RDC/ICSD-2, ICD-10, and DSM-IV-TR diagnoses (0.92-0.95). Conclusions: These results show that the BIQ generates accurate estimates of the prevalence and correlates of hierarchy-free insomnia in the America Insomnia Survey.