Stanford Sleepiness Scale (SSS)
| Name of questionnaire | Stanford Sleepiness Scale (SSS) |
| Type of questionnaire-description | Self-rating scale which is used to quantify progressive steps in sleepiness at a certain point in time. |
| Number of items | Not applicable |
| Number of domains/categories | 1 |
| Name of categories/domains | Degree of sleepiness |
| Scaling of items | Seven –point Likert-type scale has descriptors ranging from “feeling active, vital alert, or wide awake” (score = 1) to “no longer fighting sleep, sleep onset soon and having dream-like thoughts” (score = 7) |
| Scoring available: with permission or free | Free |
| Scoring test-retest reliability | 0.88 |
| Scoring Internal consistency | Not available |
| Validity | Validity of mean SSS using the Wilkinson addition and vigilance tests was reported at correlation of 0.68 |
| Language | English |
| Translations in other languages (if yes, then list the languages) | Not applicable |
| Developer name | E. Hoddes, V. Zarcone, H. Smythe, R. Phillips, W. C. Dement |
| Developer contact information | William C. Dement, M.D., Ph.D. Professor of Psychiatry and Sleep Medicine Department of Psychiatry and Behavioral Sciences Stanford University School of Medicine 1050A Arastradero Rd. Palo Alto, CA 94304 Ph: 650-723-6320 Fax: 650-723-8134 |
| Availability of questionnaire: needs permission from developer, cost or freely available | Freely available |
| References (original publication) | Quantification of Sleepiness: A New Approach.Psychophysiology Volume 10, Issue 4, pages 431–436, July 1973 |
| Limitations | Questionable reliability in chronic sleep deprivation, cumulative partial sleep deprivation and narcoleptics |
| Link to the questionnaire (if available) | http://www.stanford.edu/~dement/sss.html |
| Other comments | It can be administered many times per day, correlates with standard measures of performance, and reflects the effects of sleep loss. |
Last Reviewed: June 2016
