title: Exploring the role of contextual factors in disability models.
abstract: OBJECTIVE
  The objective of this paper is to define and categorize the types of relationships that contextual factors have within models of disability according to the WHO International Classification of Disability, Functioning, and Health (ICF) conceptual scheme.
  
  
  METHODS
  A conceptual analysis building on the disability literature specifies the causal relationships for contextual factors in relation to the association between activity limitation and participation using a person with arthritis as an example.
  
  
  RESULTS
  From a statistical point of view, in relation to disability process, contextual factors can act as an independent factor, confounding factor, moderating factor, and mediating factor. How the role of a particular contextual factor is specified depends on the researcher's hypothesized disability framework and research goals. Moderating and mediating contextual factors are of particular importance in disability model specification. Various sub-types of moderating contextual factors are also identified.
  
  
  CONCLUSIONS
  This paper provides a framework for the conceptualization of contextual factors in the examination of disability models. This framework has implications in constructing conceptual models as well as for setting up analytical plans. In light of the increasing awareness and application of the ICF model, we intend this work to stimulate additional discussion on this topic.
authors.affiliation: Faculty of Medicine, Memorial University of Newfoundland, Toronto, Canada. pwang@mun.ca
authors.forename: P Peter
authors.initials: PP
authors.lastname: Wang
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Badley
authors.forename: Monique
authors.initials: M
authors.lastname: Gignac
mesh_terms: D000203:Activities of Daily Living; D015986:Confounding Factors, Epidemiologic; D004185:Disability Evaluation; D006233:Persons with Disabilities / Q000145:classification* / Q000534:rehabilitation*; D015987:Effect Modifier, Epidemiologic; D004777:Environment; D006305:Health Status Indicators; D006801:Humans; D008954:Models, Biological; D008960:Models, Psychological; D014944:World Health Organization