In order to adequately implement a survey, it is necessary to consider how a suitable estimate for the target population can be made on the basis of the survey data. This also includes the calculation of design and adjustment weights.
In our consulting activities in the area of Survey Statistics , we focus on the problems associated with the estimation of population values. In addition to consulting on the weighting of survey data, we share our expertise on the imputation of missing values, non-response bias analysis, and variance estimation. We are happy to advise and support you on these topics with our experience.
A "weight" is a multiplicative factor that can be used for any analysis of a survey data set with the aim of obtaining a less biased estimator for the population. A basic distinction is made between design and calibration weights. While design weights are indispensable for surveys with different selection probabilities, calibration can reduce potential nonresponse bias and the variance of the estimator.
Imputation describes the process of replacing missing values with existing or estimated values using auxiliary variables to obtain a complete data set. Imputation is usually done at the item level and allows working with a complete data set. GESIS has many years of experience in the use of imputation procedures and advises on the appropriate imputation strategy for the respective survey data set.
Nonresponse bias can arise when participants in a survey differ systematically from non-participants. If the reasons for non-participation are associated with target variables, it is not possible to reliably infer the population parameter from the responses. Nonresponse bias analysis allows us to assess these biases. We give recommendations for dealing with nonresponse bias and point out possible limitations of surveys, when these suffer from nonresponse bias.
We have compiled various sets of information and hands-on guidelines on frequently occurring consulting topics. These already answer many questions that may arise when planning a study and collecting data. You can find this information under Basic Knowledge.
Our consulting services in the form of 'helping you to help yourself' are free of charge. Additionally, we are happy to support you with more in-depth services, which are fee-based. You will find further information in our pricing overview. (74 kB)