ESENER-PSR 2009 - European Agency for Safety and Health at Work

ends much earlier: the largest size-class for which stratified statistical information is available
for these countries is 100+.
For the sampling, these differences had no major implications since address providers usually
deliver their addresses in finer breakdowns or with the absolute number of employees, so an
adequate selection of addresses for the various cells of the sampling matrix is possible on
base of the standardized sampling matrix.
1.3.2 Employee vs. establishment-proportional sampling and weighting – some
general remarks
There are generally two possibilities of sampling and weighting: “employee proportional” and
“establishment proportional”. The choice between employee and establishment proportional
samples is not arbitrary. Both methods of sampling have their advantages and disadvantages.
It depends on the analytical focus which of the units is the more adequate one.
Many of the establishment surveys in fact are employee proportional but are analysed as if
they were establishment proportional. Unfortunately the results are often published without
giving sufficient information on whether the data are “employee proportional” or “establishment
proportional”. We would like to demonstrate the importance of the difference by giving an
example:
If – in an employee proportional sample – we find out that 60% of the answering
establishments carry out risk assessments, this does not mean that in reality 60%
of all existing establishments do this, because in the employee proportional
sample large establishments (which are more likely to carry out risk assessments)
are overrepresented and small establishments (which are less likely to carry them
out) are underrepresented. When analysing employee representative data
therefore one should better say that “60% of all employees work in establishments
which carry out risk assessments”. For statements related to the overall number of
establishments as such one has to transform the sample and will find out that the
percentage of establishments with risk assessments is much lower which is due to
the relatively large number of small establishments in reality. This example is
accordingly applicable for other findings such as e.g. on the incidence of OSH
action plans within the establishment.
Both a strict employee proportional and a strict establishment proportional sample have major
disadvantages:
When using a strict establishment-proportional sample, only an extremely low number of
interviews would be realized in large establishments with many employees. Interviews
would heavily concentrate on the smaller units which might be quite different from larger
ones with regard to working-time practices, social dialogue, forms of payment etc. For
employee-proportional weighting and analyses, the number of interviews realized in the
large establishments would be too small to allow any generalizations. In Belgium, for
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