title: Factor structure and measurement invariance of the Women's Health Initiative Insomnia Rating Scale.
abstract: As part of the Women's Health Initiative Study, the 5-item Women's Health Initiative Insomnia Rating Scale (WHIIRS) was developed. This article summarizes the development of the scale through the use of responses from 66,269 postmenopausal women (mean age = 62.07 years, SD = 7.41 years). All women completed a 10-item questionnaire concerning sleep. A novel resampling technique was introduced as part of the data analysis. Principal-axes factor analysis without iteration and rotation to a varimax solution was conducted for 120,000 random samples of 1,000 women each. Use of this strategy led to the development of a scale with a highly stable factor structure. Structural equation modeling revealed no major differences in factor structure across age and race-ethnic groups. WHIIRS norms for race-ethnicity and age subgroups are detailed.
authors.affiliation: Department of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA. dlevine@wfubmc.edu
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Levine
authors.forename: Robert M
authors.initials: RM
authors.lastname: Kaplan
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Kripke
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Bowen
authors.forename: Michelle J
authors.initials: MJ
authors.lastname: Naughton
authors.forename: Sally A
authors.initials: SA
authors.lastname: Shumaker
mesh_terms: D000367:Age Factors; D000368:Aged; D005006:Ethnicity / Q000706:statistics & numerical data; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008875:Middle Aged; D011159:Population Surveillance; D017698:Postmenopause; D012494:Sampling Studies; D007319:Sleep Initiation and Maintenance Disorders / Q000188:drug therapy* / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D016387:Women's Health