Surveys using a list-based sampling
frame
Sampling for Internet-based surveys using a
list-based sampling frame can be conducted
just as one would for a traditional survey
using a sampling frame. Simple random
sampling in this situation is straightforward
to implement and requires nothing more
than contact information (generally an e-mail
address for an Internet-based survey) on each
unit in the sampling frame. Of course, though
only contact information is required to field
the survey, having additional information
about each unit in the sampling frame is
desirable to assess (and perhaps adjust for)
nonresponse effects.
While Internet-based surveys using listbased
sampling frames can be conducted
either via the web or by e-mail, if an allelectronic
approach is preferred the invitation
to take the survey will almost always be
made via e-mail. And, because e-mail lists
of general populations are generally not
available, this survey approach is most
applicable to large homogeneous groups for
which a sampling frame with e-mail addresses
can be assembled (for example, universities,
government organizations, large corporations,
etc). Couper (2000) calls these ‘list-based
samples of high-coverage populations’.
In more complicated sampling schemes,
such as a stratified sampling, auxiliary information
about each unit, such as membership
in the relevant strata, must be available and
linked to the unit’s contact information. And
more complicated multi-stage and cluster
sampling schemes can be difficult or even
impossible to implement for Internet-based
surveys. First, to implement without having
to directly contact respondents will likely
require significant auxiliary data, which is
unlikely to be available except in the case
of specialized populations. Second, if (nonInternet
based) contact is required, then the
researchers are likely to have to resort to
the telephone or mail in order to ensure that
sufficient coverage and response rates are
achieved.
An example of multi-stage sampling procedure,
used for an Internet-based survey of realestate
journalists for which no sampling frame
existed, is reported by Jackob et al. (2005).
For this study, the researchers first assembled a
list of publications that would have journalists
relevant to the study. From this list a stratified
random sample of publications was drawn,
separately for each of five European countries.
They then contacted the managing editor
at each sampled publication and obtained
the necessary contact information on all
of the journalists that were ‘occupied withreal-estate issues’. All of the journalists
identified by the managing editors were then
solicited to participate in a web survey.
Jackob et al. (2005) concluded that it ‘takes
a lot of effort especially during the phase
of preparation and planning’ to assemble the
necessary data and then to conduct an Internetbased
survey using a multi-stage sampling
methodology.