Non-manipulable domains for the Borda count

We characterize the preference domains on which the Borda count satises Arrow's "independence of irrelevant alternatives" condition. Under a weak richness condition, these domains are obtained by xing one preference ordering and including all its cyclic permutations ("Condorcet cycles"). We then ask on which domains the Borda count is non-manipulable. It turns out that it is non-manipulable on a broader class of domains when combined with appropriately chosen tie-breaking rules. On the other hand, we also prove that the rich domains on which the Borda count is non-manipulable for all possible tie-breaking rules are again the cyclic permutation domains.

Nash implementable domains for the Borda count

We characterize the preference domains on which the Borda count satisfies Maskin monotonicity. The basic concept is the notion of a "cyclic permutation domain" which arises by fixing one particular ordering of alternatives and including all its cyclic permutations. The cyclic permutation domains are exactly the maximal domains on which the Borda count is strategy-proof when combined with every possible tie breaking rule. It turns out that the Borda count is monotonic on a larger class of domains. We show that the maximal domains on which the Borda count satisfies Maskin monotonicity are the "cyclically nested permutation domains" which are obtained from the cyclic permutation domains in an appropriately specified recursive way. ------ *We thank József Mala for posing the question of Nash implementability on restricted domains that led to this research. We are very grateful to two anonymous referees and an associate editor for their helpful comments and suggestions. The second author gratefully acknowledges financial support from the Hungarian Academy of Sciences (MTA) through the Bolyai János research fellowship.

Formal professional relationships between general practitioners and specialists: possible associations with patient health and pharmacy costs

This article investigates whether the strength of formal professional relationships between general practitioners (GPs) and specialists (SPs) affects either the health status of patients or their pharmacy costs. To this end, it measures the strength of formal professional relationships between GPs and SPs through the number of shared patients and proxies the patient health status by the number of comorbidities diagnosed and treated. In strong GP–SP relationships, the patient health status is expected to be high, due to efficient care coordination, and the pharmacy costs low, due to effective use of resources. To test these hypotheses and compare the characteristics of the strongest GP–SP connections with those of the weakest, this article concentrates on diabetes—a chronic condition where patient care coordination is likely important. Diabetes generates the largest shared patient cohort in Hungary, with the highest traffic of specialist medication prescriptions. This article finds that stronger ties result in lower pharmacy costs, but not in higher patient health statuses. Key points for decision makers • The number of shared patients may be used to measure the strength of formal professional relationships between general practitioners and specialists. • A large number of shared patients indicates a strong, collaborative tie between general practitioners and specialists, whereas a low number indicates a weak, fragmented tie. • Tie strength does not affect patient health—strong, collaborative ties between general practitioners and specialists do not involve better patient health than weak, fragmented ties. • Tie strength does affect pharmacy costs—strong, collaborative ties between general practitioners and specialists involve significantly lower pharmacy costs than weak, fragmented ties. • Pharmacy costs may be reduced by lowering patient care fragmentation through channelling a general practitioner’s patients to a small number of specialists and increasing collaboration between general practitioner and specialists. • Limited patient choice is financially more beneficial than complete freedom of choice, and no more detrimental to patient health.