Muslim Life in Germany - Deutsche Islam Konferenz

36 Introduction
ity in this project. Only if every member of the target population
can be contacted by telephone and therefore has a chance of
being interviewed is it possible to obtain a representative sample
(Granato 1999: 46). This condition can be qualified insofar
that distortions only occur if the part of the target population
without a telephone differs systematically from the rest (Terwin
und Lee 1988: 9).
Although it can be assumed that socially deprived households
and households with foreigners are less likely to have
landlines (Frey et al. 1990: 15), empirical studies have shown
that at a telephone density of 95.5 per cent the number of telephones
in households where foreigners live is only just below
that of German interviewees (Granato 1999: 49). A further reservation
against the suitability of telephone surveys is the fact
that young people in particular increasingly have no landline or
telephone registered in a telephone directory and this can lead
to systematic distortions, especially in surveys of migrants. 6 To
give every household member the same chance of being interviewed,
the selection of interviewees in the households was carried
out in accordance with the “kish selection grid” 7 , 8 (fig. 1).
6 The number of people who are only contactable by mobile phone increased
from 1.3 percent in 1999 to 5.9 percent in 2006. In the same period the number
of people living in a household with a landline fell from 96.5 percent to 92.5 percent
(Glemser 2007: 11). This means that a high landline density has so far been
guaranteed in Germany. There is no differentiation by nationality or groups of
origin.
7 The “kish selection grid” is a combination of random numbers printed on the
questionnaire. The combination of numbers is made up of the household size
and an index number for the person to be selected. For example, if 5 people live
in a household one number will be drawn from the numbers 1 to 5. If this is the
number 2, for example, the interviewer must interview the second oldest (or depending
on the instructions the second youngest) person in this 5-person household.
For further information on the use and functionality of the kish selection
grid see Schumann (2000: 101-102) or Diekmann (2003: 333-334) for example.
8 However, this cannot avoid excluding young men living alone in particular, who
have a mobile phone only, from participating in the survey. At the same time a
smaller percentage of people living alone can be expected for groups of origin