Hi! The Respondent ID for the paper-and-pencil import should be a numeric because this is the sys_respnum variable that the Lighthouse Studio will recognize for analysis, etc. You can use the third import option ("External, non-survey data") to bring in another ID you may want to reference. External data should always have the recognized sys_respnum in the first column and any new variables in the columns after that. Feel free to reach out to firstname.lastname@example.org if you more questions like this.