33 research outputs found
The Tale of Two research Communities: The Diffusion of Research on Productive Efficiency
No full textThe field of theoretical and applied efficiency analysis is pursued both by economists and people from operational research and management science. Each group tends to cite a different paper as the seminal one. Recent availability of extensive electronically accessible databases of journal articles makes studies of the diffusion of papers through citations possible. Research strands inspired by the seminal paper within economics are identified and followed by citation analysis during the 20 year period before the operations research paper was published. The first decade of the operations research paper is studied in a similar way and emerging differences in diffusion patterns are pointed out. Main factors influencing citations apart from the quality of the research contribution are reputation of journal, reputation of author, number of close followers; colleagues, “cadres of protégés”, Ph.D. students, and extent of network (“invisible college”). Such factors are revealed by the citing papers. In spite of increasing cross contacts between economics and operations research the last decades co-citation analysis reveals a relative constant tendency to stick to “own camp” references.Farrell efficiency measures, data envelopment analysis, DEA, bibliometry
Present distribution of the threatened killifish Aphanius fasciatus (Actinopterygii, Cyprinodontidae) in the Maltese Islands
No full textA survey of the nine localities from which the threatened Killifish Aphanius fasciatus has been recorded in the Maltese Islands showed that large and thriving populations exist at Salina, at the Simar and Ghadira bird sanctuaries and in reservoirs at Marsa and Ghadira. The Simar and Ghadira populations are introduced and originate from a mixture of animals collected from Salina and Marsa. The provenance of the Marsa population is unknown but it is possibly autochthonous to the Marsa area. The Salina and possibly the Marsa populations seem to be the only remaining natural populations of this species in the Maltese Islands.peer-reviewe
Double bootstrap confidence intervals in the two-stage DEA approach
No full textContextual factors usually assume an important role in determining firms' productive efficiencies. Nevertheless, identifying them in a regression framework might be complicated. The problem arises from the efficiencies being correlated with each other when estimated by Data Envelopment Analysis, rendering standard inference methods invalid. Simar and Wilson (2007) suggest the use of bootstrap algorithms that allow for valid statistical inference in this context. This article extends their work by proposing a double bootstrap algorithm for obtaining confidence intervals with improved coverage probabilities. Moreover, acknowledging the computational burden associated with iterated bootstrap procedures, we provide an algorithm based on deterministic stopping rules, which is less computationally demanding. Monte Carlo evidence shows considerable improvement in the coverage probabilities after iterating the bootstrap procedure. The results also suggest that percentile confidence intervals perform better than their basic counterpart.Peer reviewe
Data envelopment analysis and its key variants utilized in the transport sector
No full textHaving reviewed the international literature on data envelopment analysis (DEA), a non-parametric linear programming method used for efficiency evaluation, the aim of the author with the present article was to fill a gap by collecting and summarizing the essence of the main variants of DEA applied in the transport sector. Thus the DEA CCR, BCC and the Simar-Wilson method are presented. DEA CCR enables the efficiency evaluation under constant, DEA BCC under variable returns to scale. The Simar-Wilson method, also referred to as the truncated bootstrap method, is currently seen as the most reliable technique for hypothesis testing and confidence interval estimation under DEA. Some extensions, like the super-efficient DEA, the principal component analysis and the MNDEA are also highlighted. The variants included in the article were selected on the basis of their application in the transport sector, of which examples are also provided
Governance and performance: The performance of Dutch hospitals explained by governance characteristics
No full textThis paper describes the efficiency of Dutch hospitals using the Data Envelopment Analysis (DEA) method with bootstrapping. In particular, the analysis focuses on accounting for cost inefficiency measures on the part of hospital corporate governance. We use bootstrap techniques, as introduced by Simar and Wilson (J. Econom. 136(1):31–64, 2007), in order to obtain more efficient estimates of the effects of governance on the efficiency. The results show that part of the cost efficiency can be explained with governance. In particular we find that a higher remuneration of the board as well as a higher remuneration of the supervisory board does not implicate better performance.Innovation SystemsTechnology, Policy and Managemen
Stochastic Nonparametric Envelopment of Data: Combining Virtues of SFA and DEA in a Unified Framework
No full textThe literature of productive efficiency analysis is divided into two main branches: the parametric Stochastic Frontier Analysis (SFA) and nonparametric Data Envelopment Analysis (DEA). This paper attempts to combine the virtues of both approaches in a unified framework. We follow the SFA literature and introduce a stochastic component decomposed into idiosyncratic error and technical inefficiency components imposing the standard SFA assumptions. In contrast to the SFA, we do not make any prior assumptions about the functional form of the deterministic production function. In this respect, we follow the nonparametric route of DEA that only imposes free disposability, convexity, and some specification of returns to scale. From the postulated class of production functions, the proposed method identifies the production function with the best empirical fit to the data. The resulting function will always take a piece-wise linear form analogous to the DEA frontiers. We discuss the practical implementation of the method and illustrate its potential by means empirical examples.Productivity Analysis,
Migrating Possibilities: Jonathan Escoffery's "In Flux" and "Independent Living"
No full textThe first- and second-generation immigrant characters in Jonathan Escoffery’s short story collection If I Survive You (2022) struggle to belong as they navigate racism, a precarious existence in a foreign country, and familial conflicts. Both the precarity characteristic of the migrant condition and the histories of colonialism, with its enduring legacy in shaping contemporary migration flows from the so-termed Global South to the North, come to be highlighted by Escoffery through these works of short fiction. The eight stories, though they may be read as parts of a whole, are nonetheless separate, self-contained literary works. It is through his characters and their trajectories that Escoffery critiques institutionalized racism and the facile promises that the term “American dream” embodies. In this article two short stories from If I Survive You, “In Flux” and “Independent Living,” are analyzed with a view to opening up a larger academic discussion on how writers such as Escoffery, reflecting deterritorialization through the form of the short story and the English language, may be seen as opening up the borders of what may be referred to as American literary fiction. The article also explores how the character/narrator Trelawny may be seen as an attempt at autofiction by the author, whose life has followed a similar trajectory, and how that becomes an important aesthetic choice for Escoffery’s politics of literary representation of the transnational Jamaican-American community
A COMPARATIVE EVALUATION OF PETROFF’S METHOD AND NALC-NaOH DIGESTION DECONTAMINATION PROCEDURE FOR THE ISOLATION OF MYCOBACTERIA FROM CLINICAL SPECIMENS IN A TERTIARY CARE HOSPITAL
No full textHow "efficient" are dairy farms in mountain areas?
No full textPure Technical Efficiency scores of Austrian dairy farms are estimated econometrically on the basis of data envelopment analysis and bootstrapping. In a second stage, using the same assumptions on the distribution of error terms, the distances of farms to their production possibility curve are estimated as functions of farm attributes. Since some of these attributes refer to natural conditions which are more or less unfavourable, the farms in the sample are facing individual frontiers. The distinction between sectorial and individual frontiers gives rise to a distinction between “overall” and “firm-level” efficiency. Using overall efficiency for the calculation of possible savings from a move to the frontier will overestimate these savings and underestimate the efficiency of a farm relative to the conditions in which it operates.DEA, efficiency, dairy farms, Farm Management, Livestock Production/Industries,
