Methodology

The German Internet Panel (GIP) is based on a probability sample of the general German population aged 16 to 75 years. In addition, the GIP includes individuals who previously had no or limited access to the internet, i.e. who would not have been represented in any other online panel.

The first recruitment of the GIP was conducted in 2012 and resulted in a sample of 1603 persons who registered for the online panel. In 2014, a refresher sample of 3401 new persons was recruited for the GIP. An overview of the recruitment into the GIP 2012 and 2014 can be found here.

The recruitment of the GIP was conducted offline with face-to-face interviews during which all household members were invited to the online panel. This resulted in a sample of individuals clustered within households. Due to the offline recruitment the resulting sample includes persons both with and without access to the internet or a computer. To enable previously offline persons to participate in the panel the respective households were equipped with the required technology. In 2012, those persons were equipped with a BenPC, a specifically-developed easy-to-use touch-screen computer with limited functions. Persons without internet and computer recruited 2014 were equipped with a tablet pc with keyboard which was again set up for easy use with limited functions.

The Ben PC (2012)
The Tablet (2014)


Online panel members are invited to participate in online interviews every other months. The GIP questionnaires cover a diversity of topics related to current affairs (for more details please consult the questionnaires
here). The online panel methodology in connection with the probability sample of the general population enables the GIP to research both cross-sectional and longitudinal issues, to conduct randomized experiments and to react to shocks in current politics at short notice.

The response rates for each wave can be found here.

For detailed information about the methodology of the GIP please see the following articles:

Blom, A. G., Gathmann, C., & Krieger, U. (2015). Setting Up an Online Panel Representative of the General Population: The German Internet Panel. Field Methods, 27(4), 391-408. doi: 10.1177/1525822X15574494 

Blom, A. G., Bosnjak, M., Cornilleau, A., Cousteaux, A.-S., Das, M., Douhou, S., & Krieger, U. (2016). A Comparison of Four Probability-Based Online and Mixed-Mode Panels in Europe. Social Science Computer Review, 34(1), 8-25. doi: 10.1177/0894439315574825  

Blom, A. G., Herzing, J. M. E., Cornesse, C., Sakshaug, J. W., Krieger, U., Bossert, D. (2016). Does the Recruitment of Offline Households Increase the Sample Representativeness of Probability-Based Online Panels? Evidence From the German Internet Panel. Social Science Computer Review. Advanced online publication, doi: 10.1177/0894439315574825 

For detailed information regarding the face-to-face recruitment in 2012 and 2014 please see the reports of the field agency:

2012: TNS Feldbericht
2014: TNS Feldbericht