My friend has conducted a small pilot survey as part of research proposal and used anonymized results to present his case. Now adviser insists that my friend discloses names and emails of all the participants. Would it be ethical do disclose this information? Since it was a pilot study, my friend didn't bother with consent forms, and I feel like it would be incorrect to disclose this information. I understand that adviser wants to be sure that the study was real. Is there any way my friend can prove that study was real, without disclosing private information of participants?
Your friend can seek retroactive permission from the participants. They can email all of the participants to ask them for permission to disclose their contact details with the friend's advisor for the purpose of validating the survey. They should probably also ask them to complete a consent form of some kind, the details of which your friend should discuss with their advisor. Without seeking permission, it would be unethical. Depending on what the survey is about, the participants may not want their details being shared with your friend's advisor.