Axiomatic characterizations of the Choquet integral

Summary. The Choquet integral is an integral part of recent advances in decision theory involving non-additive measures. In this article we present two new axiomatic characterizations of this functional. Received: January 27, 1997; revised version: April 28, 1997     

Performance of private higher education institutions in Vietnam: evidence using DEA-based bootstrap directional distance approach with quasi-fixed inputs

Vietnam’s higher education has witnessed substantial improvements since the implementation of the Doi Moi (renovation) policy. One of the significant developments is the promotion of establishment and enhancement of the role of private institutions in national education systems. However, the quest to improve the overall performance of the private higher education institutions remains a big challenge for many stakeholders. We assess the performance of Vietnamese private universities using a data envelopment analysis–based bootstrap directional distance approach with quasi-fixed inputs. The results show that there was a large variation in the efficiency levels of private universities within and between academic years and between metropolitan and other private universities. Our empirical findings provide more insights for educational leaders and policy makers on the performance of private higher education institutions and the implications of privatization of the national higher education system.     

Threshold effects in panel data stochastic frontier models of dairy production in Canada

One of the most enduring problems in econometrics is how to properly account for heterogeneity among firms. Threshold regression models are intuitively appealing methods to deal with this issue. We consider a fixed-effect panel data stochastic frontier model (Schmidt and Sickles, 1984; Martin-Marcos and Suarez-Galvez, 2000) and, relying on Hansen (1999, 2000a), we propose an estimator that accommodates multiple thresholds. Our model assumes absence of any unmeasured time invariant heterogeneity across firms as in Greene (2005, p. 277). Slope and threshold parameters can be estimated using a within estimator combined with a grid search over the threshold parameters. Testing for threshold effects is problematic because threshold parameters are not identified under the null hypothesis, a case of the so-called Davies' problem. We apply the bootstrap procedure proposed by Hansen (1999, 2000a) to test for the presence of thresholds. An asymptotic confidence set for the threshold parameter can be obtained by inverting an LR test, using the distribution result presented in Hansen (1999, 2000a). Our empirical application features a panel of Quebec dairy farms. We use farm size as the threshold variable. The presence of a trend in the specification matters for the determination of the number of thresholds. Technical efficiency scores and rankings of farms estimated from competing model specifications are highly correlated and do not vary significantly across groups of farm sizes defined by the threshold parameter values.     

Short-run Dynamics of Machinery Demand in Canadian Agriculture

Based on the hypothesis of intertemporal cost minimization, this paper develops an error correction model to explain short-run dynamics of machinery demand in aggregate Canadian agricultural production. The estimated model is subjected to a rigorous sequence of hypothesis tests to check for its statistical validity. In addition, various versions of the model that are nested within the most general model are also tested. Structural parameters of the intertemporal cost minimization problem are recovered from the parameter estimates.     

Flexible Adjustment in the Age of Financialisation: The Case of Norway

Norway's “Government Pension Fund” – Global (GPF-G) is large (around $400b), portfolio oriented and transparent. It tries to be ethical and has been mooted as a role model for other SWFs. The way the GPF-G is set up undergirds the US vision of a financialised world economy and it even indirectly supports US warfare in Iraq by buying treasury bills. It is also a leader in ethical investments – more than 20 private funds piggyback any divestment decision the GPF-G makes. Understanding the international implications of the GPF-G does not, however, amount to an explanation of why this vehicle was created. This article puts forward the argument that if we want to understand why and how these diverse behaviours cohere into a larger strategic whole, the fund must be interpreted as the continuation and technocratisation of a long established corporatist tradition of foreign economic policy that Peter Katzenstein more than 25 years ago labelled a strategy of flexible adjustment and domestic compensation.     

Efficiency,technological change and output growth in Greek olive growing farms: a Box-Cox approach

This paper captures the relative contributions of input growth, technological change and technical efficiency to olive oil production growth for a panel data set of 125 Greek olive-growing farms for the period 1987 to 1993. A flexible generalized quadratic Box-Cox functional form is proposed to represent the underlying production technology. This functional specification copes with the problem of zero inputs and nests all widely used production frontiers. Empirical results show that the observed production growth is mainly due to increased input use since it was not accompanied by rapid introduction of technological innovations and improvements in efficiency levels.     

A cost-analysis model for anticoagulant treatment in the hospital setting

Background:

Rivaroxaban is the first oral factor Xa inhibitor approved in the US to reduce the risk of stroke and blood clots among people with non-valvular atrial fibrillation, treat deep vein thrombosis (DVT), treat pulmonary embolism (PE), reduce the risk of recurrence of DVT and PE, and prevent DVT and PE after knee or hip replacement surgery. The objective of this study was to evaluate the costs from a hospital perspective of treating patients with rivaroxaban vs other anticoagulant agents across these five populations.

Methods:

An economic model was developed using treatment regimens from the ROCKET-AF, EINSTEIN-DVT and PE, and RECORD1-3 randomized clinical trials. The distribution of hospital admissions used in the model across the different populations was derived from the 2010 Healthcare Cost and Utilization Project database. The model compared total costs of anticoagulant treatment, monitoring, inpatient stay, and administration for patients receiving rivaroxaban vs other anticoagulant agents. The length of inpatient stay (LOS) was determined from the literature.

Results:

Across all populations, rivaroxaban was associated with an overall mean cost savings of $1520 per patient. The largest cost savings associated with rivaroxaban was observed in patients with DVT or PE ($6205 and $2742 per patient, respectively). The main driver of the cost savings resulted from the reduction in LOS associated with rivaroxaban, contributing to ～90% of the total savings. Furthermore, the overall mean anticoagulant treatment cost was lower for rivaroxaban vs the reference groups.

Limitations:

The distribution of patients across indications used in the model may not be generalizable to all hospitals, where practice patterns may vary, and average LOS cost may not reflect the actual reimbursements that hospitals received.

Conclusion:

From a hospital perspective, the use of rivaroxaban may be associated with cost savings when compared to other anticoagulant treatments due to lower drug cost and shorter LOS associated with rivaroxaban.