The Broader System Begins With The Workplace

Most practitioners trained in family therapy are employed in host agencies which are not family therapy services. In these environments an ongoing challenge is to find constructive ways to manage the contraints of the employing agency. Central to meeting this challenge is the practitioner's ability to make sense of the host agency's local conditions. This paper offers a framework for developing an explicit awareness of these local conditions. It is the authors' view that an advanced level of ‘local knowledge’ allows for more creativity in managing the inevitably challenging experience of practice in human service agencies.     

Socioeconomic ramifications of changing cohort size: an analysis of U.S. postwar suicide rates by age and sex

This paper presents a relative cohort size model of suicide. The model states that as relative cohort size (the ratio of younger to older workers) rises, income and income aspirations diverge for the young. One possible extreme reaction to this disequilibrium is suicide. The model explains the variation in age- and sex-specific suicide rates for the United States over the period 1948 to 1976. It identifies the direct effect of changes in cohort size on suicide rates as well as the indirect effect operating through other demographic variables. The model predicts the suicide rates for males above 45 years of age to rise and those for all other groups to decline. For most groups this is a reversal of recent movements in their suicide rates.     

An Improved Test for Continuous Local Martingales

We present a new test for the “continuous martingale hypothesis”. That is, a test for the hypothesis that observed data are from a process which is a continuous local martingale. The basis of the test is an embedded random walk at first passage times, obtained from the well-known representation of a continuous local martingale as a continuous time-change of Brownian motion. With a variety of simulated diffusion processes our new test shows higher power than existing tests using either the crossing tree or the quadratic variation, including the situation where non-negligible drift is present. The power of the test in the presence of jumps is also explored with a variety of simulated jump diffusion processes. The test is also applied to two sequences of high-frequency foreign exchange trade-by-trade data. In both cases the continuous martingale hypothesis is rejected at times less than hourly and we identify significant dependence in price movements at these small scales.     

Geometric Ergodicity and Scanning Strategies for Two-Component Gibbs Samplers

In Markov chain Monte Carlo analysis, rapid convergence of the chain to its target distribution is crucial. A chain that converges geometrically quickly is geometrically ergodic. We explore geometric ergodicity for two-component Gibbs samplers (GS) that, under a chosen scanning strategy, evolve through one-at-a-time component-wise updates. We consider three such strategies: composition, random sequence, and random scans. We show that if any one of these scans produces a geometrically ergodic GS, so too do the others. Further, we provide a simple set of sufficient conditions for the geometric ergodicity of the GS. We illustrate our results using two examples.     

Accuracy,confidence and consensus in bayesian hypothesis inference

Interest centres on a group of statisticians , each supplied with the same n sample datapoint sandmaking formal Bayesian inference with a common likelihood function but differing prior knowledge and utility functions.

Definitions are proposed which quantify, in a commensurable way, the inference processes of “accuracy”, “confidence” and “consensus” for the case of hypothesis inference with a fixed sample size n.

The general significance of comparing the three quantifiers is considered. As n increases the asymptotic behaviour of the quantifiers is evaluated and it is found that the three rates of convergence are of the same order as a function of n. The results are interpreted and some of their implications are discussed.     

On the distributions of the estimated process capability indices

The exact distributions of the estimated process capability indices are presented and their means, variances, and mean-squared errors are given. The basic assumption is that the process measurements are taken from a normal distribution. Theresults in this article are useful in evaluating process capability.