Consulting

Sample design

The quality of data and their significance depend crucially on the type of sample design. In principle, two types can be distinguished here: Random samples (probability samples) and non-probability samples. Only random samples allow conclusions to be drawn from the sample to the target population. If this is not the goal of a study, non-probability samples can be a cost-effective alternative.
  
We are happy to consult you on planning the appropriate sample for your individual research project. The planning of the appropriate sample design as well as the corresponding sample size should be well-considered at the beginning of any survey and tailored to the target population (population), the survey instrument, and the general conditions of the research project (e.g. budget). GESIS supports you in this process by providing advice on sample designs and sample size planning.

Our consulting services on survey statistics and sampling

Probability samples

Probability samples provide a basis for drawing conclusions about the target population. The decisive factor here is that each unit (such as individuals or households) must have a known and positive probability of being included in the sample. We can advise you on simple and complex random samples and discuss the best approach for your research question.

Non-probability samples

Non-probability samples are samples that are drawn non-randomly or deterministically. These include quota samples and the (self-)recruitment of respondents, for example on websites or in social networks. The latter in particular is being used more and more frequently in line with the increasing use of online surveys. We advise you on the use of non-probabilistic samples for your specific research questions, discuss potential uses and pitfalls, and show you concrete options for action.

Who is this service for?
We provide consultation to researchers within the context of research and infrastructure projects, whose outputs benefit the social sciences (e.g., through publications, publicly available data, or validated measurement instruments). Unfortunately, we are unable to offer advice on bachelor's or master's theses.

What are the costs?
Short consultations, offered as a form of guidance for self-help, are free of charge. We are also happy to support you with more in-depth, fee-based consulting services. Further details can be found in our pricing overview.

Cognitive pretesting
Empirically assess the comprehensibility and validity of questions in-depth

Sampling
We draw telephone samples and complex samples for you

Weighting and analysis of complex data
We perform weighting, imputation, or nonresponse bias analyses for you

GESIS survey guides
Practical guidelines on survey methodology topics

SQP - Survey quality predictor
Estimate the measurement quality of questions using meta-analysis

Meet the Experts - Season 1: Survey Methodology
Recorded lectures from our "Meet the Experts" series

QuestionLink
Harmonization of questions for selected constructs with recoding scripts and an R package for your own projects