The POLARIS Codebook includes a list of all variables that we aim to use in the POLARIS study. This document describes the coding system that we will use in the analysis. For the PDF format of the codebook, please click here.  

To harmonize variables in the POLARIS dataset, the data description should include the following documentation:

  • Variable name (abbreviation)
  • Short variable description
  • Format (numeric/alphanumeric)
  • Code for non-numeric variables
  • Unit of measurement
  • Code for missing values
  • Original question (English, French, Dutch, German)
  • Study protocols

If you have any questions on how to arrange the data set, we encourage you to contact us by e-mail at or by telephone at +31 20 4449931, and we can try to solve any problems before you send the data.