IBUC 2006 Abstract

Can We Reach You by Telephone?
Fannie Cobben; Statistics Netherlands, The Netherlands

The sampling frame for a telephone survey is obtained by linking telephone numbers to the names/addresses from
the Municipal Base Admininstration. This is achieved by handing over the names/addresses to the Dutch telephone
company KPN. However, such links will only be established for individuals with a listed, fixed-line number. As a
consequence, individuals with an unlisted fixed-line number, indviduals with only a mobile phone, and individuals
without a phone, will never be selected for a telephone survey. Currently, the percentage of individuals with a
listed, fixed-line number is estimated to be between 60% and 70%. This means that there is a substantial
undercoverage of 30% to 40%.

Statistics Netherlands faces the challenge to produce high quality statistics under severe budget cuts imposed by
the government. One way of realising this is implementing more cost-effective modes of data collection. Statistics
Netherlands has always favoured face-to-face interviewing for its social and demographic surveys. Due to the
persuasive power and assistance of interviewers visiting selected individuals or households, nonresponse is
relatively low and data quality is high. However, the costs of this mode of interviewing are relatively high. A large
group of trained interviewers is required that is distributed all over the country. To reduce costs, Statistics
Netherlands is now considering changing some of its face-to-face surveys into telephone surveys. By concentrating
interviewers in one call centre, a smaller group is sufficient. No more time is spent on travel, and this also means
no more travel costs are involved.

Although a possible change from face-to-face interviewing to telephone interviewing may substantially reduce the
costs of the surveys, there is also a potential drawback: it may reduce the quality of the produced statistics. In this
presentation we explore the possible effects of changing the mode of data collection in one of the Statistics
Netherlands surveys: the Integrated Survey on Living Conditions, denoted by its Dutch acronym POLS; ‘Permanent
Onderzoek LeefSituatie’.

Contact: fcbn@cbs.nl