1KA uses very specific codes (negative values) to signify missing answer values (i.e. item nonresponse), which you might encounter in the 'DATA' - 'Browse' tab. The following codes are used for missing answer values:
- Value '- 1': the respondent (who otherwise answered the questionnaire) did not answer a particular question, even though their answer was expected;
- Value '- 2': the respondent did not answer the question because they did not meet the IF condition (e.g. the question was for students only, so non-students aren't shown the question and their answer value is set to -2 for that question);
- Value '- 3': the respondent stopped completing the questionnaire before the question was asked and did not get to the question at all;
- Value '- 4': the question was added after the respondent had already answered the questionnaire, so they could not answer it;
- Value '- 5': the respondent did not answer any question (their survey response is blank).
The missing values indicated by the negative numbers above must be distinguished from other missing values such as 'don't know', 'refused', etc., which also have negative values (-99, -98, etc.), and also from the value of the Status variable, which refers to the respondent's overall survey status.