title: A decade of data linkage in Western Australia: strategic design, applications and benefits of the WA data linkage system.
abstract: OBJECTIVE
  The report describes the strategic design, steps to full implementation and outcomes achieved by the Western Australian Data Linkage System (WADLS), instigated in 1995 to link up to 40 years of data from over 30 collections for an historical population of 3.7 million. Staged development has seen its expansion, initially from a linkage key to local health data sets, to encompass links to national and local health and welfare data sets, genealogical links and spatial references for mapping applications.
  
  
  CONCLUSIONS
  The WADLS has supported over 400 studies with over 250 journal publications and 35 graduate research degrees. Applications have occurred in health services utilisation and outcomes, aetiologic research, disease surveillance and needs analysis, and in methodologic research.
  
  
  RESULTS
  Longitudinal studies have become cheaper and more complete; deletion of duplicate records and correction of data artifacts have enhanced the quality of information assets; data linkage has conserved patient privacy; community machinery necessary for organised responses to health and social problems has been exercised; and the commercial return on research infrastructure investment has exceeded 1000%. Most importantly, there have been unbiased contributions to medical knowledge and identifiable advances in population health arising from the research.
authors.affiliation: Centre for Health Services Research, School of Population Health, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia. dholman@meddent.uwa.edu.au
authors.forename: C D'Arcy J
authors.initials: CD
authors.lastname: Holman
authors.forename: A John
authors.initials: AJ
authors.lastname: Bass
authors.forename: Diana L
authors.initials: DL
authors.lastname: Rosman
authors.forename: Merran B
authors.initials: MB
authors.lastname: Smith
authors.forename: James B
authors.initials: JB
authors.lastname: Semmens
authors.forename: Emma J
authors.initials: EJ
authors.lastname: Glasson
authors.forename: Emma L
authors.initials: EL
authors.lastname: Brook
authors.forename: Brooke
authors.initials: B
authors.lastname: Trutwein
authors.forename: Ian L
authors.initials: IL
authors.lastname: Rouse
authors.forename: Charles R
authors.initials: CR
authors.lastname: Watson
authors.forename: Nicholas H
authors.initials: NH
authors.lastname: de Klerk
authors.forename: Fiona J
authors.initials: FJ
authors.lastname: Stanley
mesh_terms: D016208:Databases, Factual; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D008498:Medical Record Linkage / Q000379:methods*; D016347:Medical Records Systems, Computerized / Q000266:history / Q000458:organization & administration*; D011159:Population Surveillance; D014904:Western Australia