Market stability: backward-bending supply in a laboratory experimental market. 1999 Presidential address Western Economic Association

This article investigates the stability properties of markets with backward-bending supply curves. Parameters are chosen so that the two classic models of price dynamics, the Walrasian model and the Marshallian model, give opposite predictions. The results are (1) market instability can be observed, and (2) in the backward-bending case stability is captured by the Walrasian model and the Marshallian model of dynamics is rejected. Previous experiments have demonstrated that the Marshallian model works in the forward-falling case. Thus, which theory of dynamics is appropriate for a market depends on the underlying reasons for demand and supply shapes.     

What do Care Managers do?--A Study of Working Practice in Older Peoples' Services

Correspondence to A. Weinberg, School of Community Health Sciences and Social Care, University of Salford, Allerton Building, Frederick Rd Campus, Salford, Greater Manchester M6 6PU, UK. Summary This paper explores the principal activities of local authoritystaff undertaking the role of care manager. It is based on asample of staff in a social services department specializingin older people's services. Data were obtained by asking staffto complete a diary schedule in which thirty-four job relatedactivities were grouped into five broad categories on the basisof previous research. A 57 per cent response rate was achieved.Analysis of the data revealed several findings of note. First,excluding travel, care managers spent 64 per cent of their workingweek in direct and indirect user and carer related activities.Second, administrative tasks occupied 32 per cent of their time.Third, care managers spent 27 per cent of their time in assessmentactivities compared with 7 per cent in monitoring and reviewingactivities and 5 per cent in counselling and support. Fourth,care managers spent 4 per cent of their time liaising with healthstaff. These findings are discussed in the light of previousresearch and a shift is noted in the nature of the direct contactwith the service user. The methodological limitations of thestudy are explored and the implications of these findings forusers and carers and the development of care management arrangementsare discussed.     

A random-effects model for cycle viability in fertility studies

The authors describe a random-effects fertility model based upon the assumption that the menstrual cycle viability probability varies from couple to couple according to a beta distribution. An EM algorithm is used to fit the model. The proposed estimating procedure is fully expandable to allow covariate effects on the beta variate. The method can be applied generally whenever dependency among Bernoulli trials is induced by a susceptibility state and the outcomes can be observed only in the aggregate. Based upon data from a cohort of 221 couples with no known fertility problems who were attempting pregnancy, cycle viability was found to be heterogeneous among couples. Stratification on the presence or absence of prenatal exposure of the woman to her mother's cigarette smoking revealed a statistically significant difference in the two-cycle viability distributions. Differences are discussed in the interpretation of the beta model compared to the marginal approach based upon generalized estimating equations.     

Engaging physicians in cost savings initiatives. Eliminating medication cost bias in the selection of inpatient medications

Higher cost medications pose a serious question for physician executives. Learn how common administrative databases can provide clinical resource utilization and identify success factors and barriers to devising cost-effective medical management strategies.