A few of our participants left questions in their questionnaire unanswered which, of course, leaves us with no data for this question. Otherwise our responses are on a Likert scale 1-4. Now, in spss I cannot enter n/a in one cell because then I wont be able to make an analysis for the rest of the column if I remember correctly. Obviously I also can't enter another number because that would influence the data. How do you solve this issue?