Claim: The Pittsburgh Sleep Quality Index is a questionnaire, developed by University of Pittsburgh researchers, which assesses one single component of a subject's sleep quality.
Evidence: The Pittsburgh Sleep Quality Index (PSQI) is a self-report questionnaire that assesses sleep quality over a 1-month time interval. The measure consists of 19 individual items, creating 7 components that produce one global score, and takes 5–10 minutes to complete.