Can variables and respective data be recoded (free text to numeric data) after data collection?

Question

We plan to conduct a longitudinal study. Baseline data has already been collected. We would like to now add follow up measurements, yet if we include the questions we would like to include, we are afraid, that combining both datasets might lead to a violation of anonymity. As we use the personalized links to the questionnaire, we are unable to delete the first dataset on sosci survey before continuing, as it is only connected via sosci/the links. As we have seen, that data can be changed online (https://www.soscisurvey.de/help/doku.php/de:results:modify) we are now wondering, whether it is possible to recode the variable? Or do we have to change every entry manually? We want to change free-text answers to numeric data.

Comments

Did you use personalized links based on the mailing feature or in any other way?

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Thank you for your reply. We used personalized links.

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Is that ... links with access codes, links with a REF or access URLs? That information is important for me to know how the personalization is related to your data in the database.

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We used access URLs.

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Please be aware that Access URLs do not allow you to merge the cases from different invitation waves. They are, therefore, usually not well suited for longitudinal surveys. Do you have a different way to merge the cases?