Have you added this embedded data in the survey flow as first element of survey flow?
I am not sure if contact list embedded data gets updated retroactively in data analysis, but you can try the above.

Hey rondev ,

Unfortunately it doesn't seem to add retrospectively

One of the solution can be: To create a CSV file with response id and that embedded data value. You can create this csv file using vlookup on data and analysis export and that contact list exports common field.
Then, you can create a API that would read this CSV file and for each row/ record, you can run this update response api in a loop.

rondev will this not work with the "Import" function instead, or do I have to create an API?

https://www.qualtrics.com/community/discussion/comment/27288#Comment_27288Yes, nice thought, it can work with import/export option too, but then the start date, end date of all respondent would change when you re-import it. But then again you can store this start and end date in some other embedded data, to retain them if needed.

rondev one last question (I think!). I am doing some tests with importing the data and it appears to append, not merge (i.e i will end up with a new row of data, rather than the original data being enriched) I am importing with the same response_ID but it seems to add a new ID to the imported data. Is there a way to merge appose to append do you know?

https://www.qualtrics.com/community/discussion/comment/27290#Comment_27290So this is one more thing that we need to know - Every time you import the data, it will add new rows and create new response id for the new row. So you need delete the previous data and then import it.

Thanks rondev that makes total sense

Hello, I'm trying to do this too. How did you end up retaining your start/end/recorded dates?