A rapid survey technique for ‘Appropriate technology’ ecological indicators in developing urban areas

For planners, providers and evaluators of vital services in urban areas of developing nations, the availability of sufficient environmental data is oftentimes a major stumbling block. The authors here present a low-cost, rapid survey technique for gathering information on the urban ecology. The effort is developed from and validated in a research program correlating urban neighborhood (barrio) characteristics with infant and child mortality in Cali, Colombia. The technique establishes a minimal set of indicators exhibiting variance with respect to other social indices by utilizing the combined results of a random sample questionnaire and a secondary data set gathered from various public sources. The subset of efficient indicators of quality of life is derived from the total data set by utilizing a system of ridit weights.     

Measuring Ontario's increasing housing affordability problem

This empirical study measures the prevalence and incidence of housing affordability problems in Canada in 1972, 1976, and 1983. It shows the affordability problem has not been improved by the major effort the Canadian governments made during the 1970s. Rent controls have not been adequate in reducing affordability problems. Moderate intervention in the housing market are not enough to help low income households attain affordable housing. The problem's resolution may require a major effort to stimulate housing supply, and by direct government involvement, adjustment in creating new methods and institutions for building and delivering housing services. Housing affordability problems will remain unresolved in the absence of major income redistribution programs.     

Distributions with Generalized Skewed Conditionals and Mixtures of Such Distributions

Mixtures of skewed distributions (univariate and bivariate) provide flexible models. An alternative modeling approach involves distributions with skewed conditional distributions and mixtures of such distributions. We consider the interrelationships between such models. Examples are provided to show that several skewed distributions already considered in the literature can be viewed as having been constructed via a combination of mixing and skewing.     

Asymptotics of improved generalized moment estimators for spatial autoregressive error models

Abstract

This article considers linear models with a spatial autoregressive error structure. Extending Arnold and Wied (2010) Arnold, M., Wied, D. (2010). Improved GMM estimation of the spatial autoregressive error model. Econ. Lett. 108:65–68.[Crossref], [Web of Science ®] , [Google Scholar], who develop an improved generalized method of moment (GMM) estimator for the parameters of the disturbance process to reduce the bias of existing estimation approaches, we establish the asymptotic normality of a new weighted version of this improved estimator and derive the efficient weighting matrix. We also show that this efficiently weighted GMM estimator is feasible as long as the regression matrix of the underlying linear model is non stochastic and illustrate the performance of the new estimator by a Monte Carlo simulation and an application to real data.     

The height of two types of generalised Motzkin paths

Consider Motzkin paths which are lattice paths in the plane starting at the origin, running weakly above the x-axis and after n   unit steps returning at the point (n,0)$(n,0)$. The allowed steps are the up and down steps (1,1)$(1,1)$ and (1,−1)$(1,-1)$ respectively and certain horizontal steps. We consider two types of horizontal steps that have attracted recent attention in the literature. First, we consider unit horizontal steps (1,0)$(1,0)$ coloured with k colours, secondly, we look at paths where the horizontal steps are of length k, for a non-negative integer k. Using generating functions, we study the sum of heights of such paths of size n. With the use of the Mellin transform, we find asymptotic expressions for the mean heights as n tends to infinity.     

Editorial Statement

A recently developed statistical model, called Bayesian vector autoregression, has proven to be a useful tool for economic forecasting. Such a model today forecasts a strong resurgence of growth in the second half of 1985 and in 1986.     

Unmet needs at the end of life: perceptions of hospice social workers

Among persons at the end of life, it is important to understand whether the needs of patients are being adequately addressed. In particular, in hospice settings where the emphasis is on comfort care and quality of life, we know little about the presence of unmet needs. The purpose of this study was to examine the experiences of hospice social workers in working with hospice patients who had unmet needs at the end of life. Surveys were mailed to hospice social workers (N = 212) in two Southeastern states with a response rate of 36%. Results revealed that hospice social workers perceived patients to experience a wide variety of unmet needs-more commonly at the time of admission than during subsequent patient interactions. The most common unmet need reported at both times was a decreased ability to participate in activities that make life enjoyable. In situations where unmet needs exist, social workers reported that the most common perceived reasons were patient- related psychosocial issues and family conflict/issues. Additionally, a variety of interventions were used to address unmet needs, but a large number of barriers appear to impact outcomes in the cases. Results suggest that hospice patients experience a number of unmet needs, many of which are potentially treatable problems and concerns. Hospice professionals must continue to seek ways to assess and intervene effectively with patients who have unmet needs.     

On the robustness of x-charts

In process control the simple x-charts are widely used. In determining an optimum economic design for such a control procedure the time of satisfactory production is usually assumed to be exponentially distributed. In this paper deviations from this optimistic approach are investigated by comparing E-optimal x-charts (using the assumption of an exponentially distributed lifetime) and M-optimal x-charts which are obtained by tfie pessimistic muumax principle applied to all possible lifetime distributions with the same mean value. The comparison shows that the differences between E- and M-optimal x-charts are only minor with respect to a suitable loss function and therefore, the model under consideration is verv robust against deviations from the assumption about the distribution of the time of satisfactory production.     

Variable sampling intervals for multiparameter shewhart charts

This paper considers the problem of using control charts to simultaneously monitor more than one parameter with emphasis on simultaneously monitoring the mean and variance. Fixed sampling interval control charts are modified to use variable sampling intervals depending on what is being observed from the data. Two basic strategies are investigated. One strategy uses separate control charts for each parameter, A second strategy uses a proposed single combined statistic which is sensitive to shifts in both the mean and variance. Each procedure is compared to corresponding fixed interval procedures. It is seen that for both strategies the variable sampling interval approach is substantially more efficient than fixed interval procedures.     

Comments on “Canonical Correlation in Multivariate Time Series Analysis With an Application to One-Year-Ahead and Multiyear- Ahead Macroeconomic Forecasting,” by P. W. Otter

We examine the orthogonality assumption of seasonal and nonseasonal components for official quarterly unemployment figures in Germany and the United States. Although nonperiodic correlations do not seem to reject the orthogonality assumption, a periodic analysis based on correlation functions that vary with the seasons indicates the violation of orthogonality. We find that the unadjusted data can be described by periodic autoregressive models with a unit root. In simulations we replicate the empirical findings for the German data, where we use these simple models to generate artificial samples. Multiplicative seasonal adjustment leads to large periodic correlations. Additive adjustment leads to smaller ones.