title: Measuring quality of life in women with endometriosis: tests of data quality, score reliability, response rate and scaling assumptions of the Endometriosis Health Profile Questionnaire.
abstract: BACKGROUND
  To test the data quality, scaling assumptions and scoring algorithms underlying the Endometriosis Health Profile-30 (EHP-30) questionnaire: a questionnaire developed to measure the health-related quality of life (HRQoL) of women with endometriosis.
  
  
  METHODS
  A cross-sectional postal survey to 727 women with surgically confirmed endometriosis recruited from an existing genetic linkage study (OXEGENE), The National Endometriosis Society (NES), UK and the outpatient gynaecology clinics of the Women's Centre, John Radcliffe Hospital, Oxford. Tests of data quality included secondary factor analysis, internal reliability consistency, descriptive statistics of the data, missing data levels, floor and ceiling effects and corrected item to total correlation scores.
  
  
  RESULTS
  Six hundred and ten women (83.9%) returned the questionnaire. Secondary factor analysis verified the domain structure of the EHP-30. All 11 dimensions were internally reliable with Cronbach's alpha scores ranging from 0.80 to 0.96. Missing response rates ranged from 0.2 to 1.3%, and all items were found to be most highly correlated with their own (corrected) scale.
  
  
  CONCLUSIONS
  Results confirmed the factor structure, scoring and scaling assumptions of the questionnaire. The high rate of data completeness indicated that the EHP-30 was acceptable and understandable to the respondents, thereby verifying its suitability for measuring the HRQoL of women with endometriosis.
authors.affiliation: School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, and Nuffield Department of Obstetrics and Gynaecology, Women's Centre, John Radcliffe Hospital, Oxford, UK. g.l.jones@sheffield.ac.uk
authors.forename: Georgina
authors.initials: G
authors.lastname: Jones
authors.forename: Crispin
authors.initials: C
authors.lastname: Jenkinson
authors.forename: Nicola
authors.initials: N
authors.lastname: Taylor
authors.forename: Abbie
authors.initials: A
authors.lastname: Mills
authors.forename: Stephen
authors.initials: S
authors.lastname: Kennedy
mesh_terms: D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D004715:Endometriosis / Q000235:genetics / Q000503:physiopathology* / Q000523:psychology*; D005260:Female; D006304:Health Status; D006801:Humans; D008875:Middle Aged; D011788:Quality of Life; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires