title: Selection bias of Internet panel surveys: a comparison with a paper-based survey and national governmental statistics in Japan.
abstract: OBJECTIVE
  To investigate the selection bias of an Internet panel survey organized by a commercial company.
  
  
  METHODS
  A descriptive study was conducted. The authors compared the characteristics of the Internet panel survey with a national paper-based survey and with national governmental statistics in Japan.
  
  
  RESULTS
  The participants in the Internet panel survey were composed of more women, were older, and resided in large cities. Regardless of age and sex, the prevalence of highly educated people in the Internet panel survey was higher than in the paper-based survey and the national statistics. In men, the prevalence of heavy drinkers among the 30- to 49-year-old population and of habitual smokers among the 20- to 49-year-old population in the Internet panel survey was lower than what was found in the national statistics.
  
  
  CONCLUSIONS
  The estimated characteristics of commercial Internet panel surveys were quite different from the national statistical data. In a commercial Internet panel survey, selection bias should not be underestimated.
authors: Jichi Medical University, Shimotsuke, Japan tsuboi@jichi.ac.jp.
authors: Satoshi
authors: S
authors: Tsuboi
authors: Harvard School of Public Health, Boston, MA, USA National Institute of Public Health, Wako, Saitama, Japan.
authors: Honami
authors: H
authors: Yoshida
authors: Hamasaka Public Hospital, Mikata, Japan.
authors: Ryusuke
authors: R
authors: Ae
authors: Jichi Medical University, Shimotsuke, Japan.
authors: Takao
authors: T
authors: Kojo
authors: Jichi Medical University, Shimotsuke, Japan.
authors: Yosikazu
authors: Y
authors: Nakamura
authors: Family Planninng Research Center/Clinic, Shinjuku, Japan.
authors: Kunio
authors: K
authors: Kitamura
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D020407:Internet; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D015983:Selection Bias; D011795:Surveys and Questionnaires / Q000592:standards*; D014798:Vital Statistics; D055815:Young Adult