Every case study has a corresponding survey. This page has all the links from previous studies.

Beauharnais V.S.  Illinois:   https://docs.google.com/forms/d/e/1FAIpQLSdtNPqPNOEbe8mBVIc6RA_bUf7uoEENj_0KfaftG5quy7Eaiw/viewform?usp=header