Proportion dominance
Description
Preference for proportionally higher gains, such that the same absolute quantity is valued more as the reference group decreases (e.g., saving 10/10 lives is preferred to saving 10/100 lives).
Finucane, M. L., Peters, E., & Slovic, P. (2003). Judgment and decision making: The dance of affect and reason. In S. L. Schneider & J. Shanteau (Eds.), Emerging perspectives on judgment and decision research (pp. 327–364). Cambridge, UK: Cambridge University Press.
Items (5)
In each item, two interventions are described as treating identical problems in two different populations. The (joint evaluation) items are constructed by including both a small and a large reference group. Participants are asked to rate their relative strength of preference for one intervention over the other by circling one of seven partitioning marks along a scale bounded by “Strong Preference for Program A” and “Strong Preference for Program B”.
Item 1
Anthrax powder has been weaponized and released into the air above two mid-sized cities. In each city, a number of people are expected to die as a result of anthrax inhalation. There exists a powerful antibiotic that will successfully treat some victims, but there is a limited amount of this treatment.
Program A would delegate the treatment to City A, and 225 of the 300 at risk of death will be saved.
Program B would delegate the treatment to City B, and 230 of the 920 people at risk of death will be saved.
These programs are mutually exclusive and the only two options available.
Item 2
An amusement park is nearing the final stages of planning before construction when it is found that construction will destroy some trees where an endangered species of songbird nests. The planners are willing to adopt one of two proposed solutions to the problem.
Program A saves 19 of the 25 birds that nest Area A.
Program B saves 20 of the 400 birds that nest in Area B.
These programs are mutually exclusive and the only two options available.
Item 3
The current recession has forced companies to cut jobs. Your office provides financial support to struggling businesses in the local economy, but limited resources force you to choose which businesses to assist.
Program A saves 54 of the 60 jobs that would have otherwise been lost at Factory A.
Program B saves 56 of the 560 jobs that would have otherwise been lost at Factory B.
These programs are mutually exclusive and the only two options available.
Item 4
An oil spill around Puget Sound is threatening the sea otter populations in two areas of the bay. Two cleanup plans are proposed, but there is only enough money to support one plan. So, there are only enough resources to save otters in one of these areas of the bay.
Program A will save 120 of the 150 otters near the north end of the bay.
Program B will save 124 of the 800 otters near the south end of the bay.
These programs are mutually exclusive and the only two options available.
Item 5
You are on a committee at a major paper company with two factories on a mid-sized river. These factories use water from the river to cool their machines. Once used, the water is exhausted back into the stream. This polluted water causes a number of fish to die every year near the factory from which it is exhausted. Filters can be installed that will save a number of fish, but filter installation is expensive, and there is only enough money in the budget to install filters at one factory.
Program A filters the water exhausted from Factory A, resulting in the prevention of 245 of the annual 350 fish deaths due to pollution.
Program B filters the water exhausted from Factory B, preventing 251 of the annual 980 fish deaths due to pollution.
These programs are mutually exclusive and the only two options available.
Scoring
Responses at the end of the scale corresponding to a strong preference for the intervention that maximized absolute savings are coded as zeros; responses at the end of the scale corresponding to a strong preference for the intervention maximizing relative savings are coded as ones.
This yields a measure of proportion dominance in joint evaluation, with responses coded by their difference (from zero to one) from the absolute savings end of the scale.
Source
Bartels, D. M. (2006). Proportion dominance: The generality and variability of favoring relative savings over absolute savings. Organizational Behavior and Human Decision Processes, 100(1), 76–95.