I have some survey response data that are inconsistent and I'm not sure what is the best way to handle them. This is the nature of the inconsistency:
- Have you ever had a food poisoning episode that you think might have been caused by the food in a particular restaurant ? a) Yes b) No
- Did any of these episodes prevent you from eating at that restaurant again? a) Does not apply, never have had a food poisoning episode b) Yes c) No
- Following these episodes, did you come back to your normal condition after 24 hours? a) Does not apply, never have had a food poisoning episode b) Yes c) No
I believe that the intent of the designers of the survey was that anyone answering "No" to 1) should answer "Does not apply" to 2) and 3), but that's not how it worked. A large group of respondents picked "No" for 1) and "No" for at least one of 2) or 3).
What is the best way to deal with this inconsistency?
Where are some good references (books, papers, websites, etc.) to look at discussions and solutions for issues of this kind, and data cleaning in general?