But in the real world monitoring is not costless and information and enforcement
are not perfect. A standard of efficiency impossible to achieve in the
real world is not a useful test against which to define market failure. The test
of efficiency should still be that a Pareto improvement is impossible to find,
but such an improvemenmt ustb e soughtt akingi nto accountt he imperfections
of informationa nd enforcementh at the marketi n questionh as to deal withthat
is using the concepto f constrainedP aretoe fficiency.B y this standard,t he
outcome described above, where the lender reduced the amount lent to a borrower
because of monitoring difficulties, could in fact be efficient in a constrained
sense. The information problem may still have an efficiency cost to
society, but from an operationalp oint of view that cost has no relevance.
The argument that problems in credit markets result in a lower level of output,
and perhapst oo much risk-takingr elativet o some ideal situationw here
informationi s freelya vailable,i s frequentlyu sed to justifys ubsidizedc redito r
the establishmento f government-ownebda nksi n areast hat appeart o be poorly
served by the public sector. This argument is a non sequitur and should be
resisted whenever encountered. In thinking about market failure and constrainedP
aretoe fficiency,t he full set of feasibilityc onstraintsf or allocatingr esourcesn
eeds to be consideredI. n this article,m arketf ailurei s taken to mean
the inabilityo f a free markett o bring about a constrainedP areto-efficienat llocation
of credit, in the sense defined above (see Dixit 1987 for a sample formal
analysis).T he rest of the articlee xaminest he implicationso f this concept.
Applyingt he criteriono f constrainedP aretoe fficiencyn arrowst he field for
market failure, but it still leaves room for a fairly broad array of cases in which
resourcesc ould end up beingi nefficientlya llocated.I n the illustrationo f Pareto
improvement used above, only the well-being of the two individuals involved
in a trade was considered. But if externalities enter the picture in other