SURVEY METHODS
Sampling Method
The main sample of the survey1 is drawn once a year in two stages: in the first stage
localities (approximately 235 each year) are sampled relative to their size; in the
second stage dwellings are sampled in selected localities, so that the sampling
probability is the same for all the dwellings. In most urban localities the dwellings’
sample is taken from local authorities’ files of municipal taxes. In localities that have
no municipal tax files, the sample is taken from a list of households received from the
locality.
The original sample is supplemented by housing units that are not included in the
municipal tax files and in the lists received from the localities:
(1) Current addition of new dwellings that were occupied after the updating of
municipal tax files.
(2) Current addition of households in East Jerusalem that are sampled after
mapping of enumeration cells in the 1995 Population and Housing Census.
(3) Current addition of housing units in student dormitories, in absorption centres
and in hotels that house new immigrants.
(4) Permanent addition of households and persons in other institutions and small
localities that are not included in the current samples of the survey, and that
were sampled from the 1995 Population and Housing Census files (permanent
samples).
A. Estimation Method
The data collected in the survey are entered, reviewed and coded. After these
procedures, estimates are calculated from each quarterly sample, as explained
below. The annual estimates presented in this publication are arithmetical averages
of the quarterly four estimates.
In order to obtain estimates of the entire survey population, the data collected in the
quarterly sample are “weighted,” by assigning a coefficient (“weight”) to each of the
respondents. To this end, the population is divided into weighting groups defined by
age*sex*locality.
1
Source of data: Central Bureau of Statistics. Labour Force Surveys – 2007 (Publication No. 1345),
CBS (Jerusalem, 2008).
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The estimation method is intended to reduce both the sampling errors and the
possible biases due to the difference that may occur between households that did not
respond and households that participated in the survey.
In 1998 a new estimation method was introduced in the survey. In the new method a
weight is determined for each household interviewed; the weight is identical for each
person belonging to the same household. Thus the weight of a household expresses
the number of households and the number of persons in the survey population that a
household represents. This is in contrast to the estimation method that was used up
to 1998, when the weights of persons were obtained without relation to the
composition of the household, so uniform weights for the various household members
were not obtained.
The set of weights is determined in an iterative process. At the end of this process,
the weighted distribution of persons is compatible with the current demographic
estimates of the CBS, which are based on the census of 1995. In 2002 several
changes were made in the definition of weighting groups.1
1
Detailed explanations can be seen in the publication: Central Bureau of Statistics. Labour Force
Surveys – 2007 (Publication No. 1345), CBS (Jerusalem, 2008).
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