title: Estimating patient demographic profiles from practice location.
abstract: OBJECTIVE
  To test the accuracy of imputing a practice population's average socioeconomic characteristics (such as average education levels and average income) using census data centred on the location of the practice.
  
  
  METHODS
  Comparison of census data with survey data collected in primary care offices.
  
  
  METHODS
  Ontario.
  
  
  METHODS
  A cross-sectional sample of patients from 116 urban practices.
  
  
  METHODS
  Patient data were compared with census data at different levels of aggregation using mean absolute relative error (ARE), median ARE, and Spearman rank correlations.
  
  
  RESULTS
  A total of 4413 patient surveys were collected. Differences between patient profiles and census data were large. Most mean AREs were clustered between 0.70 and 0.80, and median AREs were as high as 1.67. Correlations were low (ρ = 0.02) to moderate (ρ = 0.48). These results held across both levels of aggregation.
  
  
  CONCLUSIONS
  The use of imputation techniques based on practice location is inadvisable, given the large differences that were observed.
authors.affiliation: McGill University, Montreal, Que. michael.shortt@mail.mcgill.ca
authors.forename: Michael
authors.initials: M
authors.lastname: Shortt
authors.forename: William
authors.initials: W
authors.lastname: Hogg
authors.forename: Rose Anne
authors.initials: RA
authors.lastname: Devlin
authors.forename: Grant
authors.initials: G
authors.lastname: Russell
authors.forename: Laura
authors.initials: L
authors.lastname: Muldoon
mesh_terms: D019352:Censuses; D003430:Cross-Sectional Studies; D003625:Data Collection; D003710:Demography / Q000706:statistics & numerical data*; D005194:Family Practice / Q000706:statistics & numerical data*; D006801:Humans; D009864:Ontario; D011320:Primary Health Care / Q000706:statistics & numerical data*; D011365:Professional Practice Location; D012959:Socioeconomic Factors; D018709:Statistics, Nonparametric; D014505:Urban Population