SHORTS.DOC DRAFT: COMr\l1ENTS AND CRITICISM WELCOME EFFICIENCY, GROWTH AND CONCENTRATION: AN EMPIRICAL ANALYSIS OF HOSPITAL MARKETS*
نویسندگان
چکیده
Taking an evolutionary view of markets, Harold Demsetz hypothesized that firms ., differ persistently in efficiency and that industry concentration results from growth of ., efficient firms at the expense of inefficient ones. We test the hypothesis with high quality microdata from the US hospital industry, an industry of keen policy and scientific interest. We measure efficiency by firm in the early 1980s and relate it to subsequent growth of efficient firms, to the persistence of profit differences and to changes in the concentration of markets. Initial hospital efficiency and subsequent growth (and profitability) are significantly and positively related. Also, greater initial variation in hospital efficiency within local markets is positively related to subsequent growth in market concentration. These findings support the logic ofDemsetz's evolutionary efficiency hypothesis, though they cannot confirm the stronger idea that variation in firm efficiency is the dominant explanation for changes in concentration.
منابع مشابه
Gains from diversification on convex combinations: A majorization and stochastic dominance approach
By incorporating both majorization theory and stochastic dominance theory, this paper presents a general theory and a unifying framework for determining the diversification preferences of risk-averse investors and conditions under which they would unanimously judge a particular asset to be superior. In particular, we develop a theory for comparing the preferences of different convex combination...
متن کاملImproved immunogenicity of tetanus toxoid by Brucella abortus S19 LPS adjuvant.
BACKGROUND Adjuvants are used to increase the immunogenicity of new generation vaccines, especially those based on recombinant proteins. Despite immunostimulatory properties, the use of bacterial lipopolysaccharide (LPS) as an adjuvant has been hampered due to its toxicity and pyrogenicity. Brucella abortus LPS is less toxic and has no pyrogenic properties compared to LPS from other gram negati...
متن کاملSteady electrodiffusion in hydrogel-colloid composites: macroscale properties from microscale electrokinetics.
A rigorous microscale electrokinetic model for hydrogel-colloid composites is adopted to compute macroscale profiles of electrolyte concentration, electrostatic potential, and hydrostatic pressure across membranes that separate electrolytes with different concentrations. The membranes are uncharged polymeric hydrogels in which charged spherical colloidal particles are immobilized and randomly d...
متن کاملPerturbative Analysis of Dynamical Localisation
In this paper we extend previous results on convergent perturbative solutions of the Schrödinger equation of a class of periodically timedependent two-level systems. The situation treated here is particularly suited for the investigation of two-level systems exhibiting the phenomenon of (approximate) dynamical localisation. We also present a convergent perturbative expansion for the secular fre...
متن کاملCollinear contextual suppression
The context of a target can modulate behavioral as well as neural responses to that target. For example, target processing can be suppressed by iso-oriented surrounds whereas it can be facilitated by collinear contextual elements. Here, we present experiments in which collinear elements exert strong suppression whereas iso-oriented contextual surrounds yield no contextual modulation--contrary t...
متن کاملAssociation between the synonymous variant organic cation transporter 3 (OCT3)-1233G>A and the glycemic response following metformin therapy in patients with type 2 diabetes
OBJECTIVES Organic cation transporter 3 (OCT3) as a high-capacity transporter contribute to the metabolism of metformin. The present study was conducted to determine the genotype frequencies of the variant OCT3-1233G>A (rs2292334) in patients with newly diagnosed type 2 diabetes (T2D) and its relationship with response to metformin. MATERIALS AND METHODS This study included 150 patients with ...
متن کامل