Does Part–whole Bias Exist? An Experimental Investigation

Abstract

The existence of part-whole bias has been hotly disputed in the recent contingent valuation literature. This paper reports on an experiment into part-whole bias. Employing vouchers for parts of a restaurant meal and using an incentive compatible procedure, valuations of the parts and of the whole were elicited. The sum of the valuations of the parts consistently exceeded that of the whole, providing evidence of the existence of part-whole bias in a context where traditional explanations would not have predicted it.

An adding-up test on contingent valuations of river and lake quality

“…The amount by which the sum of the parts exceeds the whole is substantially smaller in Bateman et al (1997) than in the studies, including ours, of CV for public goods. Bateman et al (1997) find that the sum of the parts exceeded the whole by 5.3-16% in their experimental bidding for private goods, while we find that the sum of the parts in our CV study of a public good exceeds the whole by more than 200%.…”

“…Bateman et al (1997) find that the sum of the parts exceeded the whole by 5.3-16% in their experimental bidding for private goods, while we find that the sum of the parts in our CV study of a public good exceeds the whole by more than 200%. This comparison suggests that deviations from the adding-up condition -whether they arise from the elicitation method or from true preferences -are less severe with experimental bidding for private goods than with CV methods for public goods.…”

“…Bateman et al (1997) used bidding in an experimental laboratory setting to measure respondents' WTP or WTA for vouchers for two components of a meal (the main course and dessert). Respondents were given an endowment of money and vouchers (one, two, or none).…”

Willingness to pay methods in health care: a sceptical view

“…First, WTP responses tend to be undersensitive -although not necessarily totally insensitive -to the magnitude of benefit [10][11][12]. This includes both 'scope effects', involving different quantities of the same good, and 'nesting effects' (or 'embedding effects' or 'part-whole bias'), involving one good incorporated within a larger bundle of goods.…”

Testing independence conditions in the presence of errors and splitting effects

“…1 Some of the reported violations of EU might be at least partly caused by errors instead of being intrinsic violations. Several recent studies conclude that this may indeed be true, see Blavatskyy (2006) for violations of betweenness, Sopher and Gigliotti (1993), Regenwetter and Stober (2006), Schmidt (2008, 2009) for violations of transitivity, and Schmidt and Hey (2004), Butler and Loomes (2007), and Berg, Dickhaut, and Rietz (2009) for preference reversals.…”