Epworth Sleepiness Scale: ESS and ESS-CHAD
Learn about the Epworth Sleepiness Scale (ESS), which measures general daytime sleepiness, and ESS-CHAD, the version for children and adolescents. This site explains the questionnaires, their strengths and limitations, research evidence and licensing requirements.
Start with the adult ESS or ESS-CHAD. For authorised use, see licensing information. Explore all of the site's content below.
This is a personal website of Dr Murray Johns from Melbourne, Australia. It deals with the Epworth Sleepiness Scale (ESS) and the Epworth Sleepiness Scale for Children and Adolescents (ESS-CHAD), which Dr Johns developed.
The ESS measures a person’s general level of daytime sleepiness, or their average sleep propensity in daily life (ASP). It is a simple questionnaire based on retrospective reports of the likelihood of dozing off or falling asleep in a variety of different situations. The ESS is the most commonly used method for measuring a person’s ASP, used worldwide in many different languages.
The ESS should be used with a clear understanding of what it measures, and what its strengths and limitations are.
Dr Johns owns the copyright of the ESS (copyright © MW Johns, 1990, 1997) and the ESS-CHAD (copyright © MW Johns, 1990, 2015).
A license is required to use these questionnaires.
License fees are payable by some, but not all users.
This website describes the ESS and the ESS-CHAD, the conceptual framework within which these questionnaires were developed, how they were developed, what they measure, their psychometric properties, and how to obtain a license to use them.
