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).     

Types of cooperation partners as determinants of innovation failures

In this paper we analyse if specific R&D cooperation partners are related to an increase in the probability of innovation failures in terms discontinuing innovation projects. We distinguish between seven different R&D cooperation partner types, and we discriminate between product innovation failures and process innovation failures. Using German Community Innovation Survey data we find that, firstly, each type of R&D cooperation partner has a different effect on innovation failures. Secondly, we show that product innovation failures and process innovation failures are not affected in equal measure by the same type of R&D cooperation partner. Our results suggest that while R&D cooperation with public research institutes is significantly and negatively related to the probability to cancel a process innovation project, the coefficient is positive but insignificant for product innovation failures. Firms conducting partnerships with suppliers, however, run the risk of both product and process innovation failures. In turn, cooperation with competitors is positively correlated only to process innovation failures.     

On the uniqueness of individual demand at almost every price system

A simple new proof, based on Fubini's theorem, is given for the uniqueness of individual demand at almost every price system, even if preferences are nonconvex.     

The probability of a “gross” violation of an efficient markets variance inequality

This note considers the small sample bias of the empirical variances of observed and ex-post-rational prices of financial assets, and shows that this can be much more severe than has previously been thought.     

Reference groups and individual deprivation

We provide an axiomatization of Yitzhaki's index of individual deprivation. Our result differs from an earlier characterization due to Ebert and Moyes in the way the reference group of an individual is represented in the model.     

The predictive accuracy of credit ratings: Measurement and statistical inference

Credit ratings are ordinal predictions of the default risk of an obligor. The most commonly used measure for evaluating their predictive accuracy is the Accuracy Ratio, or equivalently, the area under the ROC curve. The disadvantages of these measures are that they treat default as a binary variable, thus neglecting the timing of default events, and they fail to use all of the information available from censored observations. We present an alternative measure which is related to the Accuracy Ratio but does not suffer from these drawbacks. As a second contribution, we study statistical inference for the Accuracy Ratio and the proposed measure in the case of multiple cohorts of obligors with overlapping lifetimes. We derive methods which use more sample information and lead to tests which are more powerful than alternatives which filter just the independent part of the dataset. All procedures are illustrated in the empirical section using a dataset of S&P Credit Ratings.     

Income comparisons and attitudes towards foreigners - Evidence from a natural experiment

We exploit a natural experiment related to the German re-unification to address whether disutility from income comparisons affects attitudes towards foreigners. Our empirical approach rests upon East German individuals with West German relatives and friends. We use the exogenous variation of wealth of West Germans shortly after the fall of the Berlin Wall as an instrument to identify the effect of disutility from income comparisons on East Germans’ attitudes. We find robust evidence that East Germans express more negative attitudes towards foreigners, particularly from low-wage countries, if they worry about their economic status compared to better-off West Germans.     

Tax Interaction Effects,Environmental Regulation,and “Rule of Thumb” Adjustments to Social Cost

Preexisting distortions in factor markets complicate the estimation of the social welfare effects of regulatory interventions. The existence of these tax interaction effects (TIEs) suggests that general equilibrium (GE) approaches should be used to evaluate regulatory policies. However, formal GE analysis is not always feasible for the numerous environmental regulations proposed by federal, state, and local agencies. The question addressed in this paper is whether an empirically based rule of thumb upward adjustment factor is appropriate to properly scale social cost estimates in environmental policy. We argue that such rule of thumb adjustments are significantly less reliable than estimates based on a detailed general equilibrium analysis because of the uncertainty about both the magnitude and sign of the social cost distortion. In addition to addressing this question, the paper gives an overview of TIEs and their relevance to environmental policy.     

North–South models of intellectual property rights: an empirical critique

Do Southern intellectual property rights (IPRs) affect Northern innovation? There is much theoretical debate on the impact of IPRs in the South on the incentives of Northern firms to innovate and transfer technologies to the South. While empirical research exists on the effects of Southern IPRs on Northern technology transfers, empirical evidence on the effects of Southern IPRs on Northern innovation is absent. This paper seeks to fill that gap. Using a comprehensive micro-database of US multinational firms and their foreign affiliates in developed countries, this study finds that patent protection in the South has statistically insignificant effects on the research and development of these firms. Rather, the patent regimes of developed countries matter significantly to the R&;D of these firms. Developing countries constitute a relatively small share of the world market so that variations in the patent rights of developing economies have contributed marginally to Northern incentives for R&;D.     

Discrimination: An interdisciplinary analysis

Discrimination on the basis of race, sex, national origin, etc., is often morally wrong. But should such behaviour be proscribed by legislation, and penalized by fines or jail sentences? This paper argues that such enactments are incompatible with the law of free association, and with the concept of economic liberty and civil rights.