Validity of random-digit-dialing in recruiting controls in a case-control study

Am J Health Behav. Sep-Oct 2009;33(5):513-20. doi: 10.5993/ajhb.33.5.4.


Objectives: To evaluate whether the participating controls represented the underlying population in a colorectal cancer case-control study in a geographically isolated North American population.

Methods: The characteristics of the study controls recruited through Random-digit-dialing (RDD) were compared with those in the corresponding target population estimates.

Results: Participating controls were more likely to have higher levels of education and income and were less likely to be smokers.

Conclusion: Study controls recruited through RDD tend to have higher socioeconomic status, which may lead to overestimation of a number of risk factors in this study.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Adult
  • Aged
  • Bias
  • Case-Control Studies*
  • Educational Status
  • Female
  • Humans
  • Male
  • Middle Aged
  • Newfoundland and Labrador
  • Patient Selection*
  • Risk Factors
  • Smoking
  • Social Class
  • Telephone