Effects of unfolding brackets on the quality of income data in a telephone survey
In most sample surveys, questions on income have high levels of nonresponse. One method of reducing nonresponse to income questions is to ask follow up questions of initial nonrespondents by using a series of unfolding bracket questions. In this approach, if the respondent does not answer an initial question on income, a follow up question is asked in which the respondent is asked if the amount in question, such as household income, is above or below a rounded figure, such as $30,000. The respondent can then be asked a series of similarly structured questions so that a range for the amount in question can be determined. This method has been found to be effective in reducing uncertainty about measures of income and wealth on other surveys (Juster and Smith, 1997; Pleis, Dahlhamer and Meyer, 2006).
Wang, K. (2010). Effects of unfolding brackets on the quality of income data in a telephone survey. Survey Practice, June.