Ronald D. Fricker

Advantages and Disadvantages of Internet Research Surveys: Evidence from the Literature:

E-mail and World Wide Web surveys have been the subject of much hyperbole about their capabilities as well as some criticism of their limitations. In this report, the authors examine what is known and not known about the use of the Internet for surveying. Specifically, they consider evidence in the literature regarding response rates, timeliness, data quality, and cost. Using this evidence, the authors evaluate popular claims that Internet-based surveys can be conducted more quickly, effectively, cheaply, and/or easily than surveys conducted via conventional modes. They find that the realities of cost and speed often do not live up to the hype. Nonetheless, it is possible to implement Internet-based surveys in ways that are effective and cost-efficient. The authors conclude that the Internet will continue to grow in importance for conducting certain types of research surveys

The nursing home at night: effects of an intervention on noise, light, and sleep.

OBJECTIVES: The sleep of nursing home residents is fragmented by frequent awakening episodes associated, at least in part, with environmental variables, including noise and light changes. The purpose of this study was to improve sleep by reducing the frequency of nighttime noise and light changes.

A one-sided MEWMA chart for health surveillance

It is often important to rapidly detect an increase in the incidence rate of a given disease or other medical condition. It has been shown that when disease counts are sequentially available from a single region, a univariate control chart designed to detect rate increases, such as a one-sided cumulative sum chart, is very effective. When disease counts are available from several regions at corresponding times, the most efficient monitoring method is not readily apparent. Multivariate monitoring methods have been suggested for dealing with this detection problem. Some of these approaches have shortcomings that have been recently demonstrated in the quality control literature. We discuss these limitations and suggest an alternative multivariate exponentially weighted moving average chart. We compare the average run-length performance of this chart with that of competing methods. We also evaluate the statistical performance of these charts when the actual increase in the disease count rate is different from the one that the chart was optimized to detect quickly. Copyright

Evaluating Statistical Methods for Syndromic Surveillance

The goals of this chapter are (1) to introduce the statistical issues in syndromic surveillance, (2) to describe and illustrate approaches to evaluating syndromic surveillance systems and characterizing their performance, and (3) to evaluate the performance of a couple of specific algorithms through both abstract simulations and simulations based on actual data.

Environmental equity and the distribution of toxic release inventory and other environmentally undesirable sites in metropolitan New York City

We study the question of environmental equity via generalized linear modeling for the metropolitan New York City region and ask whether, after accounting for socioeconomic status, particular racial/ethnic populations bear a disproportionate burden of hosting environmentally undesirable sites. Our data consist of population demographics for 2216 census tracts linked to 354 environmentally undesirable facilities, including toxic release inventory sites, hazardous waste treatment, storage, and disposal facilities, and other common urban problem sites such as landfills, incinerators, bus garages and sewage treatment plants. Using generalized linear and additive modeling techniques, we find that racial/ethnic demographics, in particular the Hispanic percentage of a tracts population, are significantly associated with the presence of potentially environmentally adverse sites. This leads us to the conclusion that, over the whole metropolitan New York City area, the Hispanic population is proximate to more sites than other populations. At the same time, we find that both Hispanics and African-Americans are more proximate to these sites in the Bronx and Queens. However, we also find indications that Hispanics and African-Americans are less likely to be proximate to the sites in Manhattan. We establish an empirical relationship that warrants additional study in order to establish the causes for the population distribution and whether a basis for a claim of discrimination exists.

Attrition models of the Ardennes campaign

This paper revisits the modeling by Bracken [3] of the Ardennes campaign of World War II using the Lanchester equations. It revises and extends that analysis in a number of ways: (1) It more accurately fits the model parameters using linear regression; (2) it considers the data from the entire campaign; and (3) it adds in air sortie data. In contrast to previous results, it concludes by showing that neither the Lanchester linear or Lanchester square laws fit the data. A new form of the Lanchester equations emerges with a physical interpretation.

Some methodological issues in biosurveillance.

This paper briefly summarizes a short course I gave at the 12th Biennial Centers for Disease Control and Prevention (CDC) and Agency for Toxic Substances and Disease Registry (ATSDR) Symposium held in Decatur, Georgia on April 6, 2009. The goal of this short course was to discuss various methodological issues of biosurveillance detection algorithms, with a focus on the issues related to developing, evaluating, and implementing such algorithms.

Detecting When a Monotonically Increasing Mean Has Crossed a Threshold

For monitoring a sequence of random variables, the cumulative sum (CUSUM) sequential change-point detection scheme has optimality properties if the mean experiences a single, one-time jump increase. However, many monitoring situations are not described..

Applying a Bootstrap Approach for Setting Reorder Points in Military Supply Systems

This paper develops and applies a nonparametric bootstrap methodology for setting inventory reorder points and a simple inequality for identifying existing reorder points that are unreasonably high. We demonstrate that an empirically based bootstrap method is both feasible and calculable for large inventories by applying it to the 1st Marine Expeditionary Force General Account, an inventory consisting of

Game Theory in an Age of Terrorism: How Can Statisticians Contribute?

20–30 million of stock for 10–20,000 different types of items. Further, we show that the bootstrap methodology works significantly better than the existing methodology based on mean days of supply. In fact, we demonstrate performance equivalent to the existing system with a reduced inventory at one-half to one-third the cost; conversely, we demonstrate significant improvement in fill rates and other inventory performance measures for an inventory of the same cost.