I have a list of responses (1500) that I wish to delete from my survey. Can I do this with some kind of upload to add a Tag to them “deleted”(and then based on that tag delete all based on the filter function) ? or is there a bulk function to delete responses based on ResponseID?
There is not a way to tag responses via upload for the purpose of deletion. You can delete responses in bulk via the UI:
There is not a great way in the UI to delete 1500 responses quickly. One option to consider could be the API:
https://apihelp.surveygizmo.com/help/surveyresponse-sub-object-v5#deleteobject – maybe a macro could let you automate this process?
Hope this gives you some options