title: Validating survey measurement scales for AIDS-related knowledge and stigma among construction workers in South Africa.
abstract: BACKGROUND
  Construction workers in South Africa are regarded as a high-risk group in the context of HIV/AIDS. HIV testing is pivotal to controlling HIV transmission and providing palliative care and AIDS-related knowledge and stigma are key issues in addressing the likelihood of testing behaviour. In exploring these issues, various studies have employed an 11-item AIDS-related knowledge scale (Kalichman and Simbayi, AIDS Care 16:572-580, 2004) and a 9-item stigma scale (Kalichman et al., AIDS Behav 9:135-143, 2005), but little evidence exists confirming the psychometric properties of these scales.
  
  
  METHODS
  Using survey data from 512 construction workers in the Western Cape, South Africa, this research examines the validity and reliability of the two scales through exploratory and confirmatory factor analysis and internal consistency tests.
  
  
  RESULTS
  From confirmatory factor analysis, a revised 10-item knowledge scale was developed (χ2 /df ratio = 1.675, CFI = 0.982, RMSEA = 0.038, and Hoelter (95 %) = 393). A revised 8-item stigma scale was also developed (χ2 /df ratio = 1.929, CFI = 0.974, RMSEA = 0.045, and Hoelter (95 %) = 380). Both revised scales demonstrated good model fit and all factor loadings were significant (p < 0.01). Reliability analysis demonstrated excellent to good internal consistency, with alpha values of 0.80 and 0.74, respectively. Both revised scales also demonstrated satisfactory convergent and divergent validity. Limitations of the original survey from which the data was obtained include the failure to properly account for respondent selection of language for completion of the survey, use of ethnicity as a proxy for identifying the native language of participants, the limited geographical area from which the survey data was collected, and the limitations associated with the convenience sample. A limitation of the validation study was the lack of available data for a more robust examination of reliability beyond internal consistency, such as test-retest reliability.
  
  
  CONCLUSIONS
  The revised knowledge and stigma scales offered here hold considerable promise as measures of AIDS-related knowledge and stigma among South African construction workers.
authors.affiliation: Department of Construction Economics and Management, University of Cape Town, Private Bag, Rondebosch, 7701, Cape Town, South Africa. Paul.Bowen@uct.ac.za.
authors.forename: Paul
authors.initials: P
authors.lastname: Bowen
authors.affiliation: Medical Research Council of South Africa and Department of Sociology, University of Cape Town, Private Bag, Rondebosch, 7701, Cape Town, South Africa.
authors.forename: Rajen
authors.initials: R
authors.lastname: Govender
authors.affiliation: School of Property, Construction and Project Management, RMIT University, Swanston Street, Melbourne, Victoria, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Edwards
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000523:psychology*; D000328:Adult; D060389:Construction Industry; D005163:Factor Analysis, Statistical; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008297:Male; D011594:Psychometrics / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D057545:Social Stigma; D013019:South Africa; D011795:Surveys and Questionnaires / Q000592:standards*; D055815:Young Adult