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Constant-Sum Paired Comparisons for Eliciting Stated Preferences: A Tutorial

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Abstract

There is growing recognition of the importance of formally including public preferences and values in societal decision-making processes. Constant-sum paired comparison (CSPC), sometimes known as a ‘budget pie’ task, is a stated preference method than can be used to elicit and measure these preferences and values. It requires respondents to allocate resources between two alternatives, and the relative allocation of this resource is assumed to reflect the importance or priority that respondents attach to the attribute levels in each alternative. CSPC is useful in addressing questions over preferences for the distribution of resources, and allows for an explicit linkage of budget constraints, opportunity costs, outcomes and group characteristics. A key property of CSPC is the ability to allocate some resources to the less preferred alternative, forcing respondents to reflect on the relative value of both alternatives, and possibly giving it an advantage in contexts such as healthcare where respondents may find it ethically difficult or objectionable to make all-or-nothing allocations. This tutorial will outline the theory underlying CSPC, and will work through a detailed example of administering and interpreting a CSPC elicitation, including defining attributes and levels, constructing experimental design, task presentation, and analysis and interpretation.

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Notes

  1. CSPC asks respondents to allocate a quantity between two alternatives, and is similar to constant-sum scaling (CSS), which asks respondents to allocate a quantity between different attributes within a single alternative. Both CSPC and CSS are sometimes referred to as ‘budget pie’ tasks, but as there are fundamental differences between the two formats, this term will be avoided here.

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Acknowledgments

The authors have no conflicts of interest to declare. Chris Skedgel and Dean Regier contributed to drafting the manuscript. Chris Skedgel conducted the data analysis, and acted as the overall guarantor. The Canadian Centre for Applied Research in Cancer Control receives core funding from the Canadian Cancer Society.

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Authors and Affiliations

  1. Maritime Strategy for Patient-Oriented Research Support Unit, Capital Health, Halifax, NS, Canada

    Chris Skedgel

  2. Atlantic Clinical Cancer Research Unit, Capital Health, Halifax, NS, Canada

    Chris Skedgel

  3. Canadian Centre for Applied Research in Cancer Control, Toronto, Canada

    Chris Skedgel & Dean A. Regier

  4. Cancer Control Research, British Columbia Cancer Agency, Vancouver, BC, Canada

    Dean A. Regier

  5. School of Population and Public Health, University of British Columbia, Vancouver, BC, Canada

    Dean A. Regier

  6. Centre for Clinical Research, Room 226, 5790 University Avenue, Halifax, NS, B3H 1V7, Canada

    Chris Skedgel

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  1. Chris Skedgel
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  2. Dean A. Regier
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Correspondence to Chris Skedgel.

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Skedgel, C., Regier, D.A. Constant-Sum Paired Comparisons for Eliciting Stated Preferences: A Tutorial. Patient 8, 155–163 (2015). https://doi.org/10.1007/s40271-014-0077-9

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