Prices over the Product Life Cycle: An Empirical Analysis

This paper explores the extent to which goods follow systematic pricing patterns over their life cycle. The theoretical literature, and anecdotal evidence, suggests that new products are often introduced at high prices which decline as the good ages while, older goods exit the market at a discount. We outline and apply a smoothing-spline approach to the estimation of life cycle pricing effects using data on two different types of goods; supermarket products (beer, canned soup and cereals) and high-tech goods (desktop and laptop computers, and personal digital assistants). We interpret these results within a simple conceptual framework and find evidence for the existence of significant life cycle pricing effects. This implies that hedonic pricing functions which exclude age are misspecified. Furthermore, in order to eliminate bias price index samples must be constructed carefully. Using a simulation we show that the bias introduced by the traditional match-model method may be non-trivial.Product life cycle; Hedonic regression; Price index; Spline smoothing

Life Cycle Pricing and the Measurement of Inflation

This paper explores the extent to which goods follow systematic pricing patterns over their life cycle. The theoretical literature, and anecdotal evidence, often suggests that new products are often introduced at high prices which decline as the good ages while, older goods exit the market at a discount. We outline and apply a smoothing-spline approach to the estimation of life cycle price effects using data on two different types of goods (desktop and laptop computers, and personal digital assistants). We interpret these results within a simple conceptual framework and find evidence for the existence of significant life cycle pricing effects. This implies that hedonic pricing functions that exclude age are misspecified. Furthermore, in order to eliminate biases in price indexes, samples must be constructed carefully. Using a simulation we show that the bias introduced by the traditional match-model method may be non-trivial.Product life cycle; Hedonic regression; Price index; Spline smoothing; Scanner data

Flexible Spatial and Temporal Hedonic Price Indexes for Housing in the Presence of Missing Data

We propose a flexible hedonic methodology for computing house price indexes that uses multiple imputation (MI) to account for missing data (a huge problem in housing data sets). Ours is the first study to use MI in this context. We also allow for spatial correlation, include interaction terms between characteristics, between regions and periods, and between regions and characteristics, and break the regressions up into overlapping blocks of five consecutive periods (quarters in our case). These features ensure that the shadow prices are flexible both across regions and time. This flexible structure makes the derivation of price indexes from the estimated regression equations far from straightforward. We develop innovative methods for resolving this problem and for splicing the overlapping blocks together to generate the overall panel results. We then use our methodology to construct temporal and spatial price indexes for 15 regions in Sydney, Australia on a quarterly basis from 2001 to 2006 and combine them to obtain an overall price index for Sydney. Our hedonic indexes differ quite significantly from the official index for Sydney published by the Australian Bureau of Statistics. We also find clear evidence of convergence in prices across regions from 2001-3 (while prices were rising), and divergence thereafter. We conclude by exploring some of the implications of these empirical findings.Real estate; House prices; Hedonic price index; Missing data; Multiple imputation; Spatial correlation

Life Cycle Pricing and the Measurement of Inflation

This paper explores the extent to which goods follow systematic pricing patterns over their life cycle. The theoretical literature, and anecdotal evidence, often suggests that new products are often introduced at high prices which decline as the good ages while, older goods exit the market at a discount. We outline and apply a smoothing-spline approach to the estimation of life cycle price effects using data on two different types of goods (desktop and laptop computers, and personal digital assistants). We interpret these results within a simple conceptual framework and find evidence for the existence of significant life cycle pricing effects. This implies that hedonic pricing functions that exclude age are misspecified. Furthermore, in order to eliminate biases in price indexes, samples must be constructed carefully. Using a simulation we show that the bias introduced by the traditional match-model method may be non-trivial

生态标签与贸易—环境争议

本文的目的是探讨生态标签方案潜在的全球环境利益，特别是对在国际上交易的商品来说，重要的是有两个原因：第一，在某些情况下，引入生态标签的推动力就是把它看成是更加贸易限制的环境政策（如进口限额或对会产生损害环境影响的商品征收关税）的替代品。然而，在这种情况下，就其对环境的影响而言，生态标签方案和贸易限制之间的替代程度是值得考虑的。第二，由于存在滥用生态标签要求作为技术贸易壁垒的可能性及遵守生态标签要求（如监督国外的生产方法）的费用，上市商品的生态标签要求或许是代价非常高昂的，考虑到这些成本出现了这样的假设：对进口商品的生态标签要求对环境产生极大的好处。本文的结构如下：第二部分阐述了生态标签方案的一些特点，并与一般的健康安全标签进行了比较。第三部分则考虑生态标签方案的政治经济意义，特别是其与贸易-一环境争端之间的关系。第四部分讨论了生态标签政策固有的激励问题并确定其作为环境政策工具的适当性。第五部分是在有关转基因有机物争论的背景下讨论这些问题，并讨论了在这种情况下出现的一些特殊问题。最后一部分是结论。译者单位：东北财经大学国际商务外语学院（116025

Mitophagy and the therapeutic clearance of damaged mitochondria for neuroprotection

Mitochondria are the foremost producers of the cellular energy currency ATP. They are also a significant source of reactive oxygen species and an important buffer of intracellular calcium. Mitochondrial retrograde signals regulate energy homeostasis and pro-survival elements whereas anterograde stimuli can trigger programmed cell death. Maintenance of a healthy, functional mitochondria network is therefore essential, and several mechanisms of mitochondrial quality control have been described. Mitochondrial dysfunction is linked to several neurodegenerative conditions including Parkinson, and Huntingdon diseases as well as Amyotrophic lateral sclerosis. Understanding the mechanisms governing mitochondrial quality control may reveal novel strategies for pharmacological intervention and disease therapy

The Hedonic Regression Time-Dummy Method and the Monotonicity Axioms

Abstract: This paper makes the point that the well-known and much applied hedonic regression time-dummy method, used to construct quality-adjusted price indexes, fails the monotonicity axioms from index theory. The paper discusses the hedonic time-dummy method and defines the monotonicity axioms in this context. A simple numerical example, using artificial data, is used to illustrate the failure of monotonicity. The reasons for this failure are identified and discussed. The frequency of the violation of monotonicity is considered for some particular cases and investigated for an actual data set. The paper concludes by considering the seriousness of the failure of monotonicity in this context and briefly looks at an alternative hedonic method that does satisfy monotonicity