Traditional MaxDiff analysis leads to relative importance/preference scores. But, there is no possible way for respondents to express that (for example) all the items are important or none of the items are important. Some researchers have worried that the relative nature of the MaxDiff judgments and resulting scale means that meaningful differences between respondents or segments of respondents are lost.
This article describes a practical way, proposed by Jordan Louviere (inventor of MaxDiff), to anchor the scale for each respondent based on an important/not important threshold. A dual-response questioning device is straightforward to include in MaxDiff questionnaires, and in analysis. The author (Orme) provides empirical evidence that the dual-response approach leads to meaningful discrimination among respondents and items, beyond the information provided by the standard MaxDiff tradeoffs. The pros and cons of the approach are discussed.