title: A Rasch analysis of the harm reduction self-efficacy questionnaire in Portugal.
abstract: BACKGROUND
  A high degree of self-efficacy is required from drug users if they are to adopt long-term abstinence-maintaining or harm-reducing behaviors. Our objective was to analyze the psychometric quality of the Harm Reduction Self-Efficacy Questionnaire (HRSEQ) with the Rating Scale Model (RSM), an extension of the Rasch Model for polytomous items.
  
  
  METHODS
  Participants were 419 drug dependents from both harm reduction low threshold methadone program and therapeutic community programs in Portugal (84.5% male).
  
  
  RESULTS
  Indicate that the original 11-category response system did not work adequately in any of the HRSEQ situations (Withdrawal, Negative emotions and Social pressure). There was no gender-related or group-related DIF and thus the findings of neither group nor gender-related difference in harm reduction self-efficacy cannot be plausibly attributed to that technical problem.
  
  
  CONCLUSIONS
  After recoding the rating scales by collapsing the eleven categories into four, the HRSEQ scores show good model fit and psychometric adequacy.
authors: Universidade Lusófona de Humanidades e Tecnologias, COPELABS, Centro de Estudos em Psicologia Cognitiva e da Aprendizagem, Ares do Pinhal, Portugal. Electronic address: paulo.jorge@ulusofona.pt.
authors: Paulo
authors: P
authors: Lopes
authors: Universidad de Salamanca, Spain.
authors: Gerardo
authors: G
authors: Prieto
authors: Universidad de Salamanca, Spain.
authors: Ana R
authors: AR
authors: Delgado
mesh_terms: D000328:Adult; D005260:Female; D040261:Harm Reduction; D006801:Humans; D008297:Male; D058850:Opiate Substitution Treatment / Q000523:psychology*; D009293:Opioid-Related Disorders / Q000523:psychology* / Q000534:rehabilitation; D011174:Portugal; D011594:Psychometrics; D020377:Self Efficacy; D011795:Surveys and Questionnaires; D013808:Therapeutic Community
keywords: Drug dependence; Harm reduction; Rasch Rating Scale Model; Self-efficacy