Incidence boxes are used to avoid wasting paper on respondents who do not qualify for an interview and to record the number of people the interviewer approached before finding someone willing and eligible to participate. Typically, an incidence box follows the first qualifying questions in the questionnaire and consists of numbers that the interviewer circles, one for each disqualified respondent. For example, the first two people the interviewer approaches do not qualify, so the interviewer circles 01 and 02. The third person qualifies and so the interviewer completes the paper questionnaire for that respondent.

How you handle incidence boxes depends on whether you want to collect the data recorded in the incidence box: