The economic value of INTUITY in aortic valve replacement

Objective: The recent development of the EDWARDS INTUITY Elite? (EIE) valve system enables the rapid deployment of a prosthetic surgical heart valve in an aortic valve replacement (AVR) procedure via both the minimally invasive (MISAVR) and conventional (CAVR) approaches. In order to understand its economic value, this study performed a cost evaluation of the EIE valve system used in a MIS rapid-deployment approach (MIS-RDAVR) vs MISAVR and CAVR, respectively, compared to standard prosthetic aortic valves.

Methods: A simulation model was developed using TreeAge (and validated with MS Excel) to compare the inpatient utilization and complication costs for each treatment arm. Thirty-day clinical end-points for the MIS-RDAVR (mortality and complications) were taken from the TRANSFORM trial; and a best evidence review of the published literature was used for the MISAVR and CAVR approaches. Studies were pooled and parameter estimates were weighted by sample size in order to compare the TRANSFORM patients. Cost data (2016 USD) were taken from the Premier database. Incremental cost and cost-effectiveness was assessed and one-way/probabilistic sensitivity analyses performed to gauge the robustness of the results.

Results: MIS-RDAVR costs $2,621 less than CAVR and had lower mortality rates, making it a superior (dominant) technology relative to CAVR. MIS-RDAVR costs $4,560 more than MISAVR, but was associated with an additional 0.20 life years-per-patient. This implies a cost-effectiveness ratio of $22,903 per-life-year-gained. Thus, MIS-RDAVR is cost-effective compared to MISAVR.

Conclusions: The EIE valve system deployed in a MIS approach appears to be a cost-effective technology compared to MISAVR and CAVR. When compared to CAVR it may achieve cost savings as well. These results suggest that MIS-RDAVR confers superior economic value compared to both standard MISAVR and CAVR via lowered key complication rates (re-operation, renal complications, wound infection, TIA, endocarditis) and utilization (cross-clamp time, hospital ward days).     

Market games with differential information and infinite dimensional commodity spaces: The core

Summary We provide an alternative proof of the existence of core allocations in exchange economies with differential information and infinite dimensional commodity spaces. We also identify a critical feature of information sharing rules that ensures nonemptiness of the core. In essence, the only condition we require on the sharing rules is that profitable insider trading be prohibited. In the absence of insider trading, balancedness is guaranteed and core nonemptiness follows.I thank Dan Arce, Erik Balder, Myrna Wooders, and Nicholas Yannelis for helpful comments. This paper is a greatly revised version of my paper entitled. A Variational Problem Arising in Market Games with Differential Information, written in August of 1991.     

Learning during audit tasks in the field: A model, methodology, and experiment

Learning during performance of auditing tasks in the field is modeled as a change in the state of an auditor's knowledge base that results from experience during performance of a task. Several hypotheses are proposed and, along with data obtained by means of behavior observation and concurrent verbal protocols, used to interpret the problem-solving behaviors of four first-year auditors who performed an unfamiliar but audit-related task in simulated auditing environments. Significant findings of learning during performance of the experimental task are reported. While the data show that the auditor-subjects continuously encountered new learning situations throughout the task, they are inconclusive regarding learning through improved knowledge content. On the other hand, significant evidence is found that the learning that did occur was manifest by a greater availability of the auditor-subjects' knowledge. The implications of these findings in terms of the nature of audit tasks and the development of more expert-like task behavior are discussed.     

Full price competition and Dupuit's defense of the long-and-short-haul “discrimination”

Condemnation of the long-and-short-haul discrimination has been nearly ubiquitous in the literature on economic theory and transportation. However, the French economist Dupuit developed a case against all transport regulation by relating it to a defense of the practice of place discrimination before the middle of the nineteenth century. He did so, moreover, within an early elaboration of a full price explanation of competitive functioning. This paper analyzes the idea in Dupuit's context and argues that this so-called form of price discrimination is actually an efficient and necessary form of the competitive process.     

A regional analysis of food consumption in China

Two “laws” are used to describe the budget shares of staple food, other food, and non-food in 28 regions in China: Working's model, which describes the budget share of (total) food as a declining linear function of the logarithm of total consumption expenditure, and a second model that describes the ratio of the budget shares of staple and other food as a double-log function of total consumption expenditure. Staple food appears to be an inferior good in the richest regions but not in the other regions.     

Optimal selling mechanisms for multiproduct monopolists: incentive compatibility in the presence of budget constraints

We analyze the nonlinear pricing problem faced by an incomplete information monopolist operating in a market populated by agents with budget constraints. We show that if other goods are available and if the monopolist's goods are nonessential relative to other goods, then there exists an optimal, individually rational, and incentive compatible selling mechanism for the monopolist (Theorem 1). Moreover, we show that a solution to all such nonlinear pricing problems exists if and only if the monopolist's goods are nonessential (Theorem 2). In the absence of nonessentiality, we show that if the monopolist's profit function is independent of quantity (e.g., if all costs are fixed), then an optimal selling mechanism exists (Theorem 3). Finally, we show that if there is reporting (of types by agents) and partial recognition of types (by the monopolist), then an optimal selling mechanism exists, even in the absence of nonessentiality, provided agents' utility functions are affine and continuous in goods (Theorem 4).     

Majority and Minority Ownership of Publicly-Traded Firms: A Test of the Value of Control Using Market Multiples

Publicly-traded companies that are controlled by other publicly-traded companies provide a unique setting in which to test whether the market values of majority and minority ownership interests are proportionate to their ownership percentages. Test results indicate that the value of subsidiary net assets and net income are greater to majority shareholders than to minority shareholders. However, comparison of asset and income valuation with a sample of diffusely-held firms indicates that this valuation asymmetry is not due to a wealth transfer from the minority to the majority owners but to a discounting of the portion of the subsidiary owned by the minority shareholders.     

Global Integration in Primary Equity Markets: The Role of U.S. Banks and U.S. Investors

We examine the costs and benefits of the global integrationof initial public offering (IPO) markets associated with thediffusion of U.S. underwriting methods in the 1990s. Bookbuildingis becoming increasingly popular outside the United States andtypically costs twice as much as a fixed-price offer. However,on its own, bookbuilding only leads to lower underpricing whenconducted by U.S. banks and/or targeted at U.S. investors. Formost issuers, the gains associated with lower underpricing outweighedthe additional costs associated with hiring U.S. banks or marketingin the United States. This suggests a quality/price trade-offcontrasting with the findings of Chen and Ritter, particularlysince non-U.S. issuers raising US$20 million–US$80 millionalso typically pay a 7% spread when U.S. banks and investorsare involved.     

The effects of innovation–cost strategy, knowledge, and action in the supply chain on firm performance

Despite the importance of supply chains within today's economy, we know little about how the knowledge of supply chains can contribute to superior performance at the firm level. Building on the resource-based view, knowledge-based view and strategic choice theory, we develop hypotheses linking two knowledge-driven supply chain phenomena (i.e., knowledge development capacity and intellectual capital), innovation–cost strategy, and action to firm-level performance. Using survey and archival data from 489 firms, we found that performance is influenced by how well knowledge development capacity and intellectual capital efforts complement alternative chain strategies. More specifically, each strategy type requires different constellations of knowledge development capacity and intellectual capital to enhance action and create superior firm performance. These results highlight the importance of supply chain phenomena for firm-level performance, and more broadly, the value of supply chains as a competitive weapon in contemporary firms.