title: Development of the sleep quality scale.
abstract: Sleep quality affects health and the overall quality of life. As the factors that influence sleep quality and their relative importance vary among individuals, a self-report method is essential. Although various questionnaires have been used to assess sleep quality, few all-inclusive assessment scales have been developed. Therefore, the purpose of this study was to develop an instrument for measuring sleep quality and to study its validity and reliability. A Sleep Quality Scale (SQS) was developed using item analysis and factor analysis on items with content validity. SQS, composed of 28 items and six factors, accounted for 62.6% of the total variance. The difference of SQS score between insomniacs and normal subjects confirmed the construct validity (t = -13.8, P = 0.000). Concurrent validity was identified by the significant correlation of SQS with the Pittsburgh Sleep Quality Index (r = 0.72, P = 0.000). The Cronbach's alpha coefficient was 0.92 for internal consistency and the correlation coefficient was 0.81 for test-retest reliability at a 2-week interval. The developed SQS was therefore confirmed to be a valid and reliable instrument for the comprehensive assessment of sleep quality.
authors.affiliation: Institute of Human Genomic Study, College of Medicine, Korea University, Seoul, Korea.
authors.forename: Hyeryeon
authors.initials: H
authors.lastname: Yi
authors.forename: Kyungrim
authors.initials: K
authors.lastname: Shin
authors.forename: Chol
authors.initials: C
authors.lastname: Shin
mesh_terms: D006801:Humans; D010865:Pilot Projects; D011788:Quality of Life; D012016:Reference Values; D015203:Reproducibility of Results; D012890:Sleep / Q000502:physiology*; D011795:Surveys and Questionnaires