Hi @Hans,
Please be informed that KoBoToolbox does not offer you the feature of merging household roster data-set with the main data-set that you have collected. The information provided below is just an idea of what you should look over to so that you could use some third party software to merge your data-set.
You generally see 2 or maybe more sheets in your downloaded xls dataset when you have repeat group questions within your survey questionnaire.
Please note that the first sheet that is generally seen when opening your xls dataset is the main dataset. This dataset contains a variable named _index . If you go to the next sheet (which should be your first repeat group sheet) you should see a variable named _parent_index .
Theoretically, the number of cases in your first sheet (default sheet) is always less then or sometimes equal to the next sheet (that contains the repeat group response). The two sheets can be merged based on your analysis requirement. Please note that the cases from _parent_index should always be matched and merged from those with the _index or vise-versa (i.e. as per your analysis requirement).
You could merge the data from these two sheets using lookup command (if you are using MS Excel ) or maybe you could also use some third party software such as SPSS , stata , R , SAS and so on.
