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A comparison of information on motor vehicle crashes as reported by written or telephone interviews
  1. A Alonso1,2,
  2. S Laguna1,
  3. M Seguí-Gómez1,3
  1. 1Department of Preventive Medicine and Public Health, School of Medicine, University of Navarra, Pamplona, Spain
  2. 2Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA
  3. 3Department of Health Policy and Management and Center for Injury Research and Policy, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
  1. Correspondence to:
 Dr M Seguí-Gómez
 Department of Preventive Medicine and Public Health, School of Medicine, University of Navarra, Irunlarrea, 1 31080 Pamplona, Spain; msegui{at}


Objective: To compare information about traffic crash injuries and kilometers driven reported in a written questionnaire with information reported in a telephone interview.

Design: Telephone and paper surveys.

Setting: The Seguimiento Universidad de Navarra (SUN, University of Navarra Follow-up) study, in Spain. The SUN study is an open enrollment cohort study with 17 000 enrolled graduates followed through biennial mailed questionnaires.

Subjects: A sample of 542 individuals from the SUN study participants.

Main outcome measure: Agreement on information about traffic crash injuries and mileage driven in a mailed questionnaire and a telephone survey.

Results: Participation was 90.4%. Considering the phone survey as the gold standard, data on traffic crash injuries in the mailed questionnaire had 83% sensitivity (95% CI 77% to 89%), 77% specificity (95% CI 71% to 82%), 74% positive predictive value (95% CI 67% to 80%), and 89% negative predictive value (95% CI 83% to 93%). Agreement beyond chance, measured by the kappa statistic, was 0.63 (95% CI 0.56 to 0.70). Correlation between questionnaire and telephone surveys and kilometers driven on average during a year assessed by the intraclass correlation coefficient was 0.64 (95% CI 0.57 to 0.70), p<0.001.

Conclusions: Information on sustained traffic crash injuries and traveled mileage over the previous two years as reported through mailed questionnaires in a highly educated population could be used in the study of associations between traffic crash injuries and a variety of risk factors.

  • reliability
  • mileage driven
  • cohort studies
  • traffic crash injury
  • Spain

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  • Competing interests: none.