OBJECTIVES: Inequality aversion parameters (IAPs) such as the Atkinson parameter represent the degree of concern for reducing a specified inequality. Such parameters can be applied to distributional cost-effectiveness analysis to illustrate efficiency and equity trade-offs. These parameters have been elicited from populations in the United Kingdom and other countries, but have not yet been reported for the United States. The study objective was to elicit an inequality aversion parameter for the US.

METHODS: We adapted a benefit trade-off (BTO) instrument used in a UK study. A Qualtrics panel was used to recruit adult respondents from the US general public from June – December 2023. The online survey comprised 1) demographics and health attitudes questions, 2) instructional videos, 3) BTO exercise. The BTO asked respondents to trade off quality-adjusted life expectancy from the better off to worse off quintiles of the US population, in terms of length and quality of life, described by factors influencing geographic social vulnerability and social determinants of health. Using established methods, logical response patterns for the BTO were classified into 15 ranks with corresponding Atkinson IAPs and a median IAP equity weight was calculated.

RESULTS: Among 1864 complete responses, an inequality aversion parameter was calculated for 1182 respondents. The sample demographics approximated US census data in regard to gender, race/ethnicity and income. The median Atkinson IAP among the sample was 12.12; the corresponding equity weight was 6.7. According to the ranked trade-off responses, 88% of our sample were willing to trade-off total health to reduce health inequality.

CONCLUSIONS: The elicited Atkinson inequality aversion parameter for the US (12.12) is comparable to that of the UK (10.95). Our results indicate that the vast majority of our sample prioritized health gains to the worse off, weighting them 6-7 times as highly as gains to the better off.