Protecting the leaders—syndromic surveillance for the G8 summit in Scotland

The G8 summit was held at the Gleneagles Hotel, Scotland, from July 6th to 8th, 2005. Leaders of the eight largest economies, and their entourages, assembled to discuss economic and political issues and the state of the world, including terrorism. Previous G8 summits had sparked off waves of protests and violence. Consequently, a huge security exercise took place in central Scotland for the 2005 summit. With Bush, Putin, Blair and a clutch of other premiers on hand, their safety had to be protected—as did their health, and that of those around them. Chris Robertson was charged with that task.     

Case–control studies with complex sampling

The use of complex sampling designs in population-based case–control studies is becoming more common, particularly for sampling the control population. This is prompted by all the usual cost and logistical benefits that are conferred by multistage sampling. Complex sampling has often been ignored in analysis but, with the advent of packages like SUDAAN, survey-weighted analyses that take account of the sample design can be carried out routinely. This paper explores this approach and more efficient alternatives, which can also be implemented by using readily available software.     

Consistent Estimation of the Structural Distribution Function

Motivated by problems in linguistics we consider a multinomial random vector for which the number of cells N is not much smaller than the sum of the cell frequencies, i.e. the sample size n . The distribution function of the uniform distribution on the set of all cell probabilities multiplied by N is called the structural distribution function of the cell probabilities. Conditions are given that guarantee that the structural distribution function can be estimated consistently as n increases indefinitely although n / N does not. The natural estimator is inconsistent and we prove consistency of essentially two alternative estimators.     

Profile upper Confidence Limits from Discrete Data

When the data are discrete, standard approximate confidence limits often have coverage well below nominal for some parameter values. While ad hoc adjustments may largely solve this problem for particular cases, Kabaila & Lloyd (1997) gave a more systematic method of adjustment which leads to tight upper limits, which have coverage which is never below nominal and are as small as possible within a particular class. However, their computation for all but the simplest models is infeasible. This paper suggests modifying tight upper limits by an initial replacement of the unknown nuisance parameter vector by its profile maximum likelihood estimator. While the resulting limits no longer possess the optimal properties of tight limits exactly, the paper presents both numerical and theoretical evidence that the resulting coverage function is close to optimal. Moreover these profile upper limits are much (possibly many orders of magnitude) easier to compute than tight upper limits.     

Using Bayesian graphical models to model biases in observational studies and to combine multiple sources of data: application to low birth weight and water disinfection by-products

Summary.  Data in the social, behavioural and health sciences frequently come from observational studies instead of controlled experiments. In addition to random errors, observational data typically contain additional sources of uncertainty such as missing values, unmeasured confounders and selection biases. Also, the research question is often different from that which a particular source of data was designed to answer, and so not all relevant variables are measured. As a result, multiple sources of data are often necessary to identify the biases and to inform about different aspects of the research question. Bayesian graphical models provide a coherent way to connect a series of local submodels, based on different data sets, into a global unified analysis. We present a unified modelling framework that will account for multiple biases simultaneously and give more accurate parameter estimates than standard approaches. We illustrate our approach by analysing data from a study of water disinfection by-products and adverse birth outcomes in the UK.     

Preserving Open Access

Abstract

Libraries have an established track record of preserving the scholarly record, but this stewardship role has generally been exercised over materials the library has purchased or otherwise acquired. With open access publishing, the library’s role in preservation is less certain, as libraries may facilitate access to a wide array of freely accessible materials without ever obtaining any copies. Additionally, the open access landscape includes many small noncommercial publishers with limited resources that may not be able to invest in long term preservation and access. In this column, Courtney McAllister, Electronic Resources Librarian at Lillian Goldman Law Library, Yale University, discusses preservation concerns and strategies for open access publications and how libraries may be affected by unstable or unpredictable long-term access.     

Serials spoken here: reports of conferences,institutes, and seminars

Abstract

Reports on the Ohio Valley Group of Technical Services Librarians (OVGTSL) Annual Conference, the April 2004 New England Technical Services Librarians (NETSL) Conference, the 2004 Acquisitions Institute at Timberline Lodge, and the 2004 Conference of the North American Serials Interest Group (NASIG).

Reports are from four conferences held in various parts of the United States and cover a wide range of topics. The Ohio Valley Group of Technical Services Librarians program emphasized the relationship between technical and public services. Education, both formal and continuing, was the theme for the New England Technical Services Librarians. Timberline Lodge hosted another Acquisitions Institute featuring sessions on new discoveries. The report on the 2004 North American Serials Group Annual Conference allows Conference Student Grant Award winner Chris Brady to include some personal reflections along with summaries of the sessions he attended.     

Influence measure for the L1 regression

Because outliers and leverage observations unduly affect the least squares regression, the identification of influential observations is considered an important and integrai part of the analysis. However, very few techniques have been developed for the residual analysis and diagnostics for the minimum sum of absolute errors, L₁ regression. Although the L₁ regression is more resistant to the outliers than the least squares regression, it appears that outliers (leverage) in the predictor variables may affect it. In this paper, our objective is to develop an influence measure for the L₁ regression based on the likelihood displacement function. We illustrate the proposed influence measure with examples.     

Head over heels in debt?

The average household in the UK is in debt to the tune of nearly £9000—and that is not including the mortgage. Consumer borrowing, on credit cards, car and retail finance deals, overdrafts and unsecured personal loans was £4525 per average UK adult at the end of February 2007. Are we drowning in debt? Chris Tapp , Associate Director of Credit Action, reports.