What type of authenticator are you using?
SSO? - you will be assured of the identity because the authentication is done outside in your SSO tool. You could add one or both of the next authenticators on top of it if you want.
Contact List? if you have a finite set of people allowed to respond, you can have them provide data to link to their list (external data reference) or pull their data (email/EDR) from an SSO authenticator. I do this sometimes so they don't have to enter any data, but I know who they are.
Passcode/password. you can assign a unique passcode/password for your survey...but you can also use this as the EDR, so each person has a different passcode.
And of course, you can combine all three. These are all native capabilities, so no coding required.