社会利益分化下的政府转型与和谐社会构建

利益博弈时代的到来对我国政府转型提出了新的要求,政府转型的价值取向和制度安排都亟待做出重大调整。通过政府转型,进行相应的制度整合和政府间协调,能够有效化解利益冲突和矛盾,对于构建和谐社会意义重大。     

Sushi or Fish Fingers? Seafood Diversity,Collapsing Fish Stocks,and Multispecies Fishery Management*

We present a model of a multispecies fishery, and we show the following. (i) Consumer preferences for seafood diversity can trigger a sequential collapse of fish stocks under open‐access fishery. (ii) The stronger the preferences are for diversity, the higher is the need for coordinated multispecies regulation. (iii) Second‐best optimal management of only one (or a few) species is less strict than socially optimal management of the same species. (iv) Myopic regulation of one species, ignoring spillovers to other species, can cause depletion of other stocks that would not be depleted under open access.     

Product innovation and firms’ ownership

This paper explores (i) the incentives for an incumbent firm to acquire an entrant willing to sell a product innovation rather than openly competing with this entrant, and (ii) in case of acquisition, the incentives to sell simultaneously both the existing products and the new one rather than specializing on a single variant. We prove that, in some circumstances, an incumbent firm can find it profitable to make an acquisition proposal to the entrant. Nevertheless, in this acquisition scenario, a product proliferation strategy is never observed at equilibrium. Furthermore, while being available for sale, sometimes the innovation simply remains unexploited.     

Economic evaluation of linaclotide for the treatment of adult patients with irritable bowel syndrome with constipation in the United States

Abstract

Objectives:

To use techniques of decision-analytic modeling to evaluate the effectiveness and costs of linaclotide vs lubiprostone in the treatment of adult patients with irritable bowel syndrome with constipation (IBS-C).

Methods:

Using model inputs derived from published literature, linaclotide Phase III trial data and a physician survey, a decision-tree model was constructed. Response to therapy was defined as (1) a ≥14-point increase from baseline in IBS-Quality-of-Life (IBS-QoL) questionnaire overall score at week 12 or (2) one of the top two responses (moderately/significantly relieved) on a 7-point IBS symptom relief question in ≥2 of 3 months. Patients who do not respond to therapy are assumed to fail therapy and accrue costs associated with a treatment failure. Model time horizon is aligned with clinical trial duration of 12 weeks. Model outputs include number of responders, quality-adjusted life-years (QALYs), and total costs (including direct and indirect). Both one-way and probabilistic sensitivity analyses were conducted.

Results:

Treatment for IBS-C with linaclotide produced more responders than lubiprostone for both response definitions (19.3% vs 13.0% and 61.8% vs 57.2% for IBS-QoL and symptom relief, respectively), lower per-patient costs ($803 vs $911 and $977 vs $1056), and higher QALYs (0.1921 vs 0.1917 and 0.1909 vs 0.1894) over the 12-week time horizon. Results were similar for most one-way sensitivity analyses. In probabilistic sensitivity analyses, the majority of simulations resulted in linaclotide having higher treatment response rates and lower per-patient costs.

Limitations:

There are no available head-to-head trials that compare linaclotide with lubiprostone; therefore, placebo-adjusted estimates of relative efficacy were derived for model inputs. The time horizon for this model is relatively short, as it was limited to the duration of available clinical trial data.

Conclusions:

Linaclotide was found to be a less costly option vs lubiprostone for the treatment of adult patients with IBS-C.     

Vertical differentiation with non-uniform consumers' distribution

This note explores a vertical differentiation model with a continuous non-uniform consumers' distribution. First, a result concerning the finiteness property obtained with uniform consumers' distribution is generalized. Second, we prove an existence result of price equilibrium when the distribution is concave. Finally, we exhibit a counter-example to the existence of price equilibrium to show that the concavity assumption is not superfluous.     

Demand under product differentiation: an empirical analysis of the US wine market*

Oversupply has led to a number of perplexities for the Australian wine industry in recent times. When disaggregated from the industry level, however, the problem can be better described as a range of attribute‐specific disequilibria. To date, the solutions to this problem have predominantly revolved around supply‐side policies of reducing output through crop thinning or vine pulling. By contrast, this paper focuses on the demand side and argues that the disequilibria may be reduced by gaining a better understanding of the demand for Australian wine. A discrete choice model of product differentiation is used to estimate the demand for wine in Australia's second largest export market, the United States. Implications of the analysis are explored.     

VERTICAL DIFFERENTIATION AND THE DISTRIBUTION OF INCOME

The paper analyses the effects of income concentration on the behaviour of a duopoly with vertical product differentiation and uncovered market. By using a trapezoid distribution, we solve explicitly for market equilibrium as a function of a mean preserving spread of the income distribution. We show that overall more concentrated incomes imply stronger product differentiation, as the presence of a large share of middle‐income consumers stimulates a price competition, whose effects are dampened through an enlargement of the quality spread. While the high‐quality advantage and market coverage increase unambiguously in the degree of income concentration, the behaviour of prices is non‐monotone in the distribution parameter.     

Quantity restrictions and endogenous quality choice

In a vertical product differentiation model under Cournot competition both foreign and domestic firms respond by lowering their investment in long-run quality for a quantity restriction at, and in the neighborhood of, the free trade import level. Average quality increases only when the low-quality foreign firm faces a substantially restrictive quota/voluntary export restraint. The change in quality depends on whether the foreign firm is of high or low quality and upon the restrictiveness of the quota. The imposition of quantity restrictions has important strategic effects on the long-run choice of quality.     

Pricing-to-Market: Price Discrimination or Product Differentiation?

We employ a vertical differentiation model to examine the potential bias in pricing-to-market results when using export unit values aggregating differentiated products. Our results show that: (i) false evidence of pricing-to-market is always found when using unit values, whether the law of one price holds or not; and (ii) the size of the bias increases with the level of product differentiation. Our simulation results support those conceptual findings. Thus, some of the positive pricing-to-market results in the literature could be an artifact of the product heterogeneity embodied in unit values rather than evidence of imperfect competition.     

Generic Advertising and Product Differentiation

This article considers whether generic advertising lowers the differentiation among competing brands of the same good. Analytical results show that if the benefits from generic advertising from increased demand are outweighed by the costs from lower product differentiation then high–quality producers will not benefit from generic promotion. Hypotheses are tested empirically under a conditional–logit approach using retail–market sales and advertising data for the U.S. prune industry. Results from this study provide evidence that generic advertising has a slight differential effect on the perceived qualities of different brands.