The difference between the WTP and the actual price is the "
consumer's surplus".
Mishan wrote, "The
consumer's surplus is the most crucial concept in the measurement of social benefits in any social cost-benefit calculation." The normative significance of consumer surplus comes from it being entirely based on individual preferences--that is, on each individual evaluating what is good or bad for himself.
See Robert Willig,
Consumer's Surplus Without Apology: Reply," 69 Am.
Bailey's
consumer's surplus formulae are derived and used to compute the welfare cost of inflation for both semi-log and log-log money demand functions.
Willig's famous article, "
Consumer's Surplus Without Apology" (Willig 1976), which defends the use of Marshallian surplus as a value measure of market welfare.
It can be argued that besides any subjective dimension the individual must pay from the same amount c, and then the opportunity cost exists no matter how large or small is the
consumer's surplus. Once more we must say that the formal relation (3) is not enough in order to understand the context.
(1976): "
Consumer's Surplus Without Apology", in American Economic Review, Volume 66 (no.
consumer surplus range from which any given
consumer's surplusBy considering the comparison of
consumer's surplus and firm's profit, we derive the interesting result that both consumers and the firm will prefer discriminatory pricing if the consumers prefer to consume more differentiated varieties.
"
Consumer's Surplus Without Apology." American Economic Review 66 (Sept.): 589-97.
At this critical value of c, the case 3 region consists of the two points ([k.sub.1], [k.sub.2]) = (.432, 2.315) and ([k.sub.1], [k.sub.2]) = (2.315, .432).(16) With these demand parameter values, the
consumer's surplus at [p.sup.*] = 0 for the two consumers are equal.