Snowball sampling by mail: application to a survey of smokers in the general population

Jean-François Etter, Thomas V Perneger
2000 International Journal of Epidemiology  
Conclusion Allowing non-eligible addressees to transmit the questionnaire to someone else doubled the response rate, produced moderate bias on some variables only and had no detectable impact on associations between smoking-related variables.
doi:10.1093/ije/29.1.43 pmid:10750602 fatcat:nbx3uojbzzbnzcxbgs4wi7t7pe