A few ideas for the survey:
- On Question 5, "Have you ever encountered problems with your radio equipment, not allowing you to communicate as required? (i.e. interference, static, sleeping VHF receiver, blocked transmission)" note that a blocked transmission isn't actually a problem with the radio equipment, but rather just another part of the radio infrastructure the FAA has setup. I answered "yes" to this even though I do not attribute a blocked transmission to my radio equipment. I hope this is what you would have preferred. (Although "blocked transmission" is also used as a cause in Q5.)
- In terms of addressing the frequency of problems with the radio in flight, I would suggest using terms such as "once per flight," "twice per flight," so on. The survey seems to imply that all pilots are flying every day or every week, which is not usually the case, even with airliner operations.
Good luck on your thesis!