Eight. The Problem of Undercoverage

  1. Jelke Bethlehem1 and
  2. Silvia Biffignandi2

Published Online: 4 OCT 2011

DOI: 10.1002/9781118121757.ch8

Handbook of Web Surveys

Handbook of Web Surveys

How to Cite

Bethlehem, J. and Biffignandi, S. (2011) The Problem of Undercoverage, in Handbook of Web Surveys, John Wiley & Sons, Inc., Hoboken, NJ, USA. doi: 10.1002/9781118121757.ch8

Author Information

  1. 1

    Statistics Netherlands, Division of Methodology and Quality, The Netherlands

  2. 2

    University of Bergamo, Center for Statistics and Analysis of Sample Surveys, Bergamo, Italy

Publication History

  1. Published Online: 4 OCT 2011
  2. Published Print: 21 OCT 2011

ISBN Information

Print ISBN: 9780470603567

Online ISBN: 9781118121757



  • internet;
  • mixed-mode survey;
  • target population;
  • undercoverage;
  • web surveys


Undercoverage occurs if the target population contains elements that do not have a counterpart in the sampling frame. Such elements can never be selected in the sample. Undercoverage in web surveys would not be a problem if those with Internet access did not differ systematically from those without it. If people with Internet access could be considered a random sample from the population, valid conclusions could be drawn from web surveys. There are several ways in which the negative effects of undercoverage can be reduced. Three approaches are discussed here. The first approach is to give Internet access to persons in the sample without it. A second approach is to conduct a mixed-mode survey. A third approach is to apply adjustment weighting. This chapter discusses the possible consequences of undercoverage and the effectiveness of correction techniques using a simulation experiment.

Controlled Vocabulary Terms

internet; surveys; web based questionnaires; Web surveys