title: How generalisable are results of studies conducted in practice-based research networks? A cross-sectional study of general practitioner demographics in two New South Wales networks.
abstract: OBJECTIVE
  To compare the demographics of general practitioners in two practice-based research networks (PBRNs) and to explore the generalisability of research findings from these PBRNs.
  
  
  METHODS
  Cross-sectional questionnaire-based study of two geographically-based PBRNs--Hunter New England Central Coast Network of Research General Practices (NRGP) and Primary Healthcare Research Network-General Practice (PHReNet-GP)--during August-September 2010. All 183 GP members of both PBRNs were invited to participate; of these, 140 (77%) participated.
  
  
  METHODS
  GPs' demographics, use of languages other than English in consultations, and previous participation in research. Practices' use of practice nurses. Socioeconomic status and rurality or urbanicity of practice location.
  
  
  RESULTS
  Compared with PHReNet-GP GPs, NRGP GPs were more likely to work in a practice employing a practice nurse (100% v 53.8%; 95% CI for difference, 30.5%-61.8%; P < 0.001), worked in larger practices (2.9 more full-time-equivalent GPs per practice; 95% CI, 2.1-3.6; P < 0.001), and were less likely to work in a major city (33.7% v 89.7%; 95% CI for difference, 42.8%-69.3%; P < 0.001). NRGP GPs also worked in practices with a different spectrum of socioeconomic disadvantage, and were less likely to have been involved in research as a researcher (35.4% v 76.9%; 95% CI for difference, 25.3%-57.8%; P < 0.001). Fewer NRGP GPs consulted in languages other than English (8.9% v 64.1%; 95% CI for difference, 39.1%-71.2%; P < 0.001). There were also differences between these and national general practice statistics.
  
  
  CONCLUSIONS
  These results suggest possible lack of generalisability of findings from some types of studies conducted in single PBRNs. In such circumstances, collaboration of PBRNs may produce more generalisable results.
authors.affiliation: Discipline of General Practice, University of Newcastle, Newcastle, NSW. parker.maginATnewcastle.edu.au
authors.forename: Parker J
authors.initials: PJ
authors.lastname: Magin
authors.forename: Melanie J
authors.initials: MJ
authors.lastname: Marshall
authors.forename: Susan M
authors.initials: SM
authors.lastname: Goode
authors.forename: Georgina L
authors.initials: GL
authors.lastname: Cotter
authors.forename: C Dimity
authors.initials: CD
authors.lastname: Pond
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Zwar
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D058006:General Practice / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009517:New South Wales; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D011320:Primary Health Care / Q000706:statistics & numerical data*; D012106:Research / Q000706:statistics & numerical data*; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires