A Theory of Nonseparable Preferences in Survey Responses

A person has nonseparable preferences when her preferences for the outcome of one issue or set of issues depend on the outcome of other issues. A model of individual-level responses to issue questions in public opinion surveys implies that when people have nonseparable preferences, their responses will change depending on the order of questions. An individual's responses may also vary over time as her perception of the status quo changes. A telephone survey of a random sample of residents of Franklin County, Ohio, reveals that much of the public has nonseparable preferences on a wide range of issues. Results from a survey experiment confirm that aggregate-level question-order effects occur on issues for which people have nonseparable preferences, and order effects do not occur on issues for which most people have separable preferences. At the individual level, people with nonseparable preferences display greater response instability across question orders than people with separable preferences, and a respondent's level of political information has little impact on response instability.