SOME ECONOMIC CONSEQUENCES OF ANTICIPATING TECHNICAL ADVANCE

Using a simple model of a long run profit maximizing firm, we investigated the consequences of foreseeing future technical advance upon the adoption of new technology, scrapping of old, and for price and output of the firm's product. To simplify the analysis and highlight the conclusions, we assumed all technologies embodied in equipment and all equipment infinitely durable. It was shown that the often-used formulas for the unit cost of using capital over a finite (rkj/(l — a^T)) or infinite (rkj) life are appropriate only if the equipment does not become outmoded during its economic life and if there are no demand shifts in that time interval. Otherwise, the current cost of using capital (ex ante) must reflect future lesser or greater earning power of that capital due to outmodedness or demand shifts. Anticipation of technical advance tends to delay scrapping of old equipment and retard installation of new, with current output smaller and price higher than if technology is stagnant. Selection among currently competing technologies is also affected by the course future technical advance is expected to follow. The economic lifetime of capital equipment is independent of the elasticity of demand for the firm's output. On the other hand anticipation of demand expansion tends to partially or wholly offset the effect of anticipating future technical advance, while expected demand decline tends to reinforce it. Uncertainty about when improved technology will appear tends to retard adoption of current best practice technology, to retard scrapping of outmoded technology, restrict output and elevate price, in comparison with pptimal policy when the time of availability is believed known. The optimal policy is unaffected when it is the magnitude of the improvement rather than its timing which is unknown.     

Changes in Americans' Policy Preferences, 1935-1979

Using responses to 3,315 survey questions asked of nationalsamples, we examine how policy preferences of Americans havechanged over the last 45 years. The data indicate that therehas been considerable stability in public opinion: responsesto half the 613 repeated policy items show no significant changeat all; approximately half the detectable changes were lessthan 10 percentage points; and rarely did preferences fluctuatesignificantly back and forth within a short time period. Foreignpolicy changes were no larger or more frequent than domestic,but they did tend to occur more abruptly. When opinion shiftsoccurred, they were not random or capricious; they were usuallyrelated to important changes in citizens' social and economicenvironments. Rapid shifts generally coincided with major eventsin international affairs or the economy.     

The negotiating style of Saudi industrial buyers: An empirical investigation

This study investigates the negotiating styles of Saudi industrial buyers. Thomas’s Topology as measured by Rahim’s instrument is used in this study. The results suggest that three are two dominant styles of negotiation in the Saudi context, namely: the competitive and collaborative styles.     

The "quality " of early care and education settings: definitional and measurement issues

There is a widespread belief that high-quality early care and education can improve children's school readiness. However, debate continues about the essential elements of a high-quality experience, about whether quality means the same things across different types of care settings, about how to measure quality, and about the level of quality that might make a meaningful difference in outcomes for children. Are the aspects of the child care environment that researchers measure the ones that are most strongly related to children's development? This article argues that the ways in which researchers currently measure early care environments are flawed and that the conclusions drawn about the relationship between these measures and outcomes for children are frequently incorrect or overstated. The article addresses four questions: How is the quality of the child care environment commonly defined and measured? Do the most commonly used measures capture the child's experience? Do they work well across all settings? Are researchers drawing the correct conclusions from studies that relate the child care environment to child outcomes? Finally, the article discusses some possible directions for future research.     

Nonparametric empirical Bayes for the Dirichlet process mixture model

The Dirichlet process prior allows flexible nonparametric mixture modeling. The number of mixture components is not specified in advance and can grow as new data arrive. However, analyses based on the Dirichlet process prior are sensitive to the choice of the parameters, including an infinite-dimensional distributional parameter G ₀. Most previous applications have either fixed G ₀ as a member of a parametric family or treated G ₀ in a Bayesian fashion, using parametric prior specifications. In contrast, we have developed an adaptive nonparametric method for constructing smooth estimates of G ₀. We combine this method with a technique for estimating α, the other Dirichlet process parameter, that is inspired by an existing characterization of its maximum-likelihood estimator. Together, these estimation procedures yield a flexible empirical Bayes treatment of Dirichlet process mixtures. Such a treatment is useful in situations where smooth point estimates of G ₀ are of intrinsic interest, or where the structure of G ₀ cannot be conveniently modeled with the usual parametric prior families. Analysis of simulated and real-world datasets illustrates the robustness of this approach.     

A Distribution-Free Control Chart Based on Order Statistics

In this article, we introduce a new distribution-free Shewhart-type control chart that takes into account the location of a single order statistic of the test sample (such as the median) as well as the number of observations in that test sample that lie between the control limits. Exact formulae for the alarm rate, the run length distribution, and the average run length (ARL) are all derived. A key advantage of the chart is that, due to its nonparametric nature, the false alarm rate and in-control run length distribution are the same for all continuous process distributions, and so will be naturally robust. Tables are provided for the implementation of the chart for some typical ARL values and false alarm rates. The empirical study carried out reveals that the new chart is preferable from a robustness point of view in comparison to a classical Shewhart-type chart and also the nonparametric chart of Chakraborti et al. (2004 Chakraborti , S. , van der Laan , P. , van de Wiel , M. A. ( 2004 ). A class of distribution-free control charts . J. Roy. Statist. Soc. Ser. C-Appl. Statist. 53 ( 3 ): 443 – 462 .[Web of Science ®] , [Google Scholar]).     

Time series analysis of stratospheric ozone

Time series analyses of monthly average total ozone measured at 37 stations throughout the world were used to estimate the extent to which the average ozone trend correlates with the depletion curve hypothesized as due to chlorofluorocarbons (CFCs). Statistical characteristics of stations in the ensemble were used to help define appropriate model and station selection criteria. The maximum likelihood procedure developed herein estimates the weighted average trend, its. variance, and the intra- and inter-station variance components of the trend. Correlations among trends at different stations are also taken into account. The models were subjected to much checking and criticism. Variations in statistical methodology are used to show that the results are insensitive to details of the model selection criteria. The method does not discriminate well between the hypothesized CFC trend and a linear trend. The trend estimates represent the sum of all long-term global effects. The variance includes all effects that differ from station-to-station. The estimated trend and 2α limits for 14 stations with 20-year records (1958-79) is an ozone increase through 1979 of (1.5+1.0) percent. At the 23 stations with shorter records, the trend is (1.0=1.7) percent. It is concluded that no significant depletion in stratospheric ozone has occurred from any cause through the end of 1979.