A re-evaluation of random-effects meta-analysis

Summary.  Meta-analysis in the presence of unexplained heterogeneity is frequently undertaken by using a random-effects model, in which the effects underlying different studies are assumed to be drawn from a normal distribution. Here we discuss the justification and interpretation of such models, by addressing in turn the aims of estimation, prediction and hypothesis testing. A particular issue that we consider is the distinction between inference on the mean of the random-effects distribution and inference on the whole distribution. We suggest that random-effects meta-analyses as currently conducted often fail to provide the key results, and we investigate the extent to which distribution-free, classical and Bayesian approaches can provide satisfactory methods. We conclude that the Bayesian approach has the advantage of naturally allowing for full uncertainty, especially for prediction. However, it is not without problems, including computational intensity and sensitivity to a priori judgements. We propose a simple prediction interval for classical meta-analysis and offer extensions to standard practice of Bayesian meta-analysis, making use of an example of studies of 'set shifting' ability in people with eating disorders.     

Social Studies Teachers’ Organization

Recent innovations in Web-based technology tools have made planning instruction with technology in mind far more doable than in years past. To aid teachers in planning with technology, tools are organized into five broad categories: communication, collaboration, presentation, organization and critical-thinking. The purpose and potential of each group of tools is explored and utilized in the development of a technology-rich unit plan on medieval China.     

五字教学法在两课教学中的应用

政治思想道德教育的全过程，是一个由知到行转化的复杂过程。它包含了知、情、意、信、行五个关键环节。因此，马列主义理论课和总想政治教育课教学应体现知、情、意、信、行五字法。这五者也是构成学生政治思想道德品质的基本要素，两课教学的过程是五个基本要素培养、提高和发展的过程。     

Follow-up of male pathological gamblers after treatment: The relationship of intellectual variables to relapse

Male pathological gamblers entering a comprehensive treatment program were followed-up for twelve months after treatment completion. Twelve month follow-up was obtained for 45 of the 66 patients entering treatment. Total abstinence was reported by 55% (n=25) of the patients located for twelve month follow-up. A relationship was found between abstinence at six month follow-up and selected subscales of the Wechsler Adult Intelligence Scale, performance scale. The implications of these findings for sub-typing gamblers are discussed.     

ASYMPTOTIC LIKELIHOOD APPROXIMATIONS USING A PARTIAL LAPLACE APPROXIMATION

Elimination of a nuisance variable is often non‐trivial and may involve the evaluation of an intractable integral. One approach to evaluate these integrals is to use the Laplace approximation. This paper concentrates on a new approximation, called the partial Laplace approximation, that is useful when the integrand can be partitioned into two multiplicative disjoint functions. The technique is applied to the linear mixed model and shows that the approximate likelihood obtained can be partitioned to provide a conditional likelihood for the location parameters and a marginal likelihood for the scale parameters equivalent to restricted maximum likelihood (REML). Similarly, the partial Laplace approximation is applied to the t‐distribution to obtain an approximate REML for the scale parameter. A simulation study reveals that, in comparison to maximum likelihood, the scale parameter estimates of the t‐distribution obtained from the approximate REML show reduced bias.     

Digital Image Processing

Many of the tasks encountered in image processing can be considered as problems in statistical inference. In particular, they fit naturally into a subjectivist Bayesian framework. In this paper, we describe the Bayesian approach to image analysis. Numerical examples are not included but can be found among the references, in the previous Special Issue of this Journal and elsewhere. It is argued that the Bayesian approach, still in its infancy, has considerable potential for future development.