Pittsburgh Sleep Quality Index (PSQI)
Psychology: Health & SleepReliability: alpha 0.833 sample items
About this scale
A 19-item measure of sleep quality and disturbances over the past month, generating a global score from seven components: sleep quality, latency, duration, efficiency, disturbances, medication use, and daytime dysfunction.
Sample item(s)
“During the past month, what time have you usually gone to bed at night?”
“During the past month, how long has it usually taken you to fall asleep each night?”
“During the past month, how would you rate your sleep quality overall?”
Reliability
Reported internal consistency: alpha 0.83. As a rule of thumb, Cronbach’s α ≥ .70 is considered acceptable, ≥ .80 good, and ≥ .90 excellent for established measures.
Notes
Free for academic use; the most cited sleep-quality instrument.
Source & citation
Buysse, D. J., Reynolds, C. F., Monk, T. H., Berman, S. R., & Kupfer, D. J. (1989): The Pittsburgh Sleep Quality Index: A new instrument for psychiatric practice and research. Psychiatry Research, Vol. 28, No. 2, pp. 193–213.
Source. Scale details are summarised from the publication cited above. Always consult the original source for the full item set, scoring, and permission to use.
Use it in your research
Need to check the reliability or psychometrics of this scale in your own data? Use the free DrAIStudio research tools:
Cronbach’s alpha calculator
All statistical calculators
Search the full Scale Atlas
Academic writing humanizer