Need a "my page"/"my account" for CPDB user, no ?
I already thinking of something like :

CPDB user login
See his page with : all survey already completed, survey to be completed etc …

But a lot of work

The "my page"/"my account" could be the second step.

I thought about giving every user in the CPDB an own token (like an employee number). This will be mapped as access token for a survey. This works completly fine, but new members of the CPDB can't access the survey. So I have to add them daily or weekly to the surveys. If there would be an option to manage that all users of the CPDB can access this survey, that would be awesome.

But I really like your idea :)