Estimating Transition Probabilities from a Time Series of Independent Cross Sections

This paper considers the implementation of a nonstationary, heterogeneous Markov model for the analysis of a binary dependent variable in a time series of independent cross sections. The model, previously considered by M offitt (1993), offers the opportunity to estimate entry and exit transition probabilities and to examine the effects of time-constant and time-varying covariates on the hazards. We show how ML estimates of the parameters can be obtained by Fisher's method-of-scoring and how to estimate both fixed and time-varying covariate effects. The model is exemplified with an analysis of the labor force participation decision of Dutch women using data from the Socio-economic Panel (SEP) study conducted in the Netherlands between 1986 and 1995. We treat the panel data as independent cross sections and compare the employment status sequences predicted by the model with the observed sequences in the panel. Some open problems concerning the application of the model are also discussed.     

Using proxies for the short rate: when are three months like an instant?

The dynamics of the unobservable short rate are frequently estimateddirectly using a proxy. We examine the biases resulting fromthis practice (the 'proxy problem'). Analytic results show thatthe proxy problem is not economically significant for single-factoraffine models. In the two-factor affine model of Longstaff andSchwartz (1992), the proxy problem is only economically significantfor pricing discount bonds with maturities of more than fiveyears. We also describe two different numerical procedures forassessing the magnitude of the proxy problem in a general interestrate model. When applied to a nonlinear single-factor model,they suggest that the proxy problem can be economically significant.     

Research returns redux: a meta-analysis of the returns to agricultural R&D

A total of 289 studies of returns to agricultural R&D were compiled and these provide 1821 estimates of rates of return. After removing statistical outliers and incomplete observations, across the remaining 1128 observations the estimated annual rates of return averaged 65 per cent overall — 80 per cent for research only, 80 per cent for extension only, and 47 per cent for research and extension combined. These averages reveal little meaningful information from a large body of literature, which provides rate-of-return estimates that are often not directly comparable. This study was aimed at trying to account for the differences. Several features of the methods used by research evaluators matter, in particular assumptions about lag lengths and the nature of the research-induced supply shift.     

Partial Pooling at the Reserve Price in Auctions with Resale Opportunities

Two features common to many auctions are the use of reserve prices and the existence of secondary markets for the goods being sold. Even in simple symmetric settings, the combination of these features can preclude existence of an equilibrium in symmetric separating bidding strategies. With a reserve price sufficiently far below the maximum (endogenous) valuation, a symmetric equilibrium still exists, but with some types pooling at the reserve. The optimal reserve price depends not only on the joint distribution of bidders' information before and after the auction, but also on how surplus is divided in the secondary market. Journal of Economic Literature Classification Numbers: D44, C7, L1, D82     

Telematics: Decision Time for Detroit

With implications for navigation, safety, entertainment and vehicle maintenance as well as regulation and infrastructure investment in roads, telematics has the potential to transform driving more than any other innovation for decades. In the already well-established Asian telematics industry, revenue tends to come from extra charges at the time of vehicle-sale, with most subsequent services provided free. The US model has evolved differently, with much of the cost of telematics hardware and software subsidized in the initial vehicle sale price and revenue coming from services used. The decision to invest in telematics is therefore riskier in the US. This article first briefly summarizes the potential of telematics. It then analyzes the investment risks, particularly for automakers. It concludes with recommendations on how the US auto industry can minimize risk and make the most of the opportunities.     

Rezensionen

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基于费用流的废纸动态回收网络优化设计

通过建立基于费用流的废纸动态回收网络模型并求解,解决废纸在运输网络中流动的路径问题,避免了经典运输问题无法直接体现转运和路径选择的问题,最后通过一个模拟算例验证了模型的优越性。     

当前发展高等教育产业需要正确把握的几个现实问题

发展高等教育产业的根本目的在于建立与社会主义市场经济相适应的高等教育体系，世纪初我国高等教育的超常规发展需要产业思想的内在动力，本从高等教育改革与发展的现实出发，提出了发展高等教育产业需要正确把握的五个问题。