Sample
The population of the main survey in the fourth quarter of every year consists all establishments in Germany with at least one employee subject to social security contributions. A stratified random sample is drawn anew every year from this population. It is stratified by region (West and East Germany), seven establishment size classes as well as 24 industries based on the German classification of industries 2008 (NACE rev. 2), creating a three-dimensional sampling matrix.
Mail survey in the fourth quarter
All establishments of the distribution sample are contacted by mail at the beginning of October and are asked to participate in the survey. In the fourth quarter, all establishments in this sample receive a letter requesting answers to a questionnaire and a brief explanation of the survey. The Institute for Labor Market and Occupational Research (IAB) commissioned the Institute Economics & Data ED23 GmbH in Munich to carry out the survey. All those contacted are asked to fill out the questionnaire by the beginning of November and return it to the survey institute. The companies and administrations that do not respond to the letter will be asked again to take part in the survey. The survey is carried out in the sequential CAWI / PAPI mixed-mode design.
Short follow-up surveys in the first, second and third quarters
In the first, second and third quarters, the establishments that took part in the main survey in the fourth quarter will be interviewed again in order to update the labor demand information during the year. They complement the main survey in the respective fourth quarter and enquire and update the most important data points in the main questionnaire, including the number of employees, the assessment of current workforce developments and the number of vacancies. The interviews last on average five minutes. Here too, the survey is carried out in the sequential CAWI / PAPI mixed-mode design.
Extrapolation
The responses of participating establishments are extrapolated using a Generalized Regression estimator (GREG) onto the level of the entire German economy. The procedure incorporates both design and non-response weights, allowing statistically valid statements on the development of labour demand and recruitment processes in the several industries and regions and for different firm sizes. Details on the current extrapolation procedure may be found in the IAB Research Report No. 4/2016 (Brenzel et al. 2016).
Yearly revision of the IAB Job Vacancy Survey
In order to provide up-to-date information on the number of vacancies as quickly as possible, data for the most recent four quarters is initially extrapolated using preliminary aggregated counts of employed workers from the Federal Employment Agency. Later every year, the extrapolation procedure that produces the total number of vacancies is repeated for the most recent survey wave using the final number of employed workers.
Publications and advisory policy
Aggregated results of the surveys are published in the form of an IAB press release at the latest six weeks after the end of each quarter. More detailed analyses are published throughout the year both in policy-oriented reports and in scientific journals. They form the basis for policy advice to the Federal Employment Agency, the Federal Ministry of Labour and Social Affairs, governmental departments of the German federal states, the German Council of Scientific Advisors, the European Commission, and the OECD. The micro data of the survey are made available to external researchers in the Research Data Centre of the Federal Employment Agency after the yearly revision.