One of the really tough things you run into is someone telling you ‘‘I don’t know’’ in answer to lots of questions. In qualitative research projects, where you choose respondents precisely because you think they know something of interest, the ‘‘don’t know’’ refrain can be especially frustrating. Converse and Schuman (1974:49) distinguish four kinds of don’t-know response: (1) I don’t know (and frankly I don’t care); (2) I don’t know (and it’s none of your business); (3) I don’t know (actually, I do know, but you wouldn’t be interested in what I have to say about that); and (4) I don’t know (and I wish you’d change the subject because this line of questioning makes me really uncomfortable). There is also the ‘‘(I wish I could help you but) I really don’t know.’’
Sometimes you can get beyond this, sometimes you can’t. You have to face the fact that not everyone who volunteers to be interviewed is a good respondent. If you probe those people for information when they say, ‘‘I don’t know,’’ you tempt them to make something up just to satisfy you, as Sanchez and Morchio (1992) found. Sometimes, you just have to take the ‘‘don’t know’’ for an answer and cut your losses by going on to someone else (box 8.3).