In order to obtain meaningful answers to research questions on the basis of survey data, i.e. to be able to draw conclusions from samples to the population, adjustments often have to be made to the data to compensate for missing values or under- or over-representation of certain groups. We advise you on weighting, imputation of missing values and non-response bias analysis. We can also carry out these analyses for you (for a fee).
Determine an unbiased or less biased estimator for the population.
Determination of imputation values to compensate for missing values.
Analysis to assess bias in results due to systematic non-response.