Statistical issues in epidemiologic studies of the health effects of ambient acid aerosols

Although the ecologic effects of acid rain have been widely reported, relatively little is known about the effects of acidic air pollution on human health. Some epidemiologic and animal studies suggest, however, that acidity is an important determinant of the respiratory health effects of aerosols. This paper reviews some of that evidence and discusses its implications for the design and analysis of epidemiologic studies. We contrast two types of exposure patterns: peak exposures associated with air pollution episodes, and chronic exposures resulting from persistently high levels of air pollutants. Recent work on the analysis of repeated categorical outcome variables provides new methods for the analysis of episode studies. Studies of long-term exposure require comparisons among population groups, and these comparisons can be subject to the design effects characteristic of multistage sample surveys. We examine the implications of these design effects for epidemiologic studies. Finally, the paper discusses the measurement errors induced by the use of outdoor measurements to quantify personal exposure to air pollutants. Recent work on methods for errors-in-variables problems may aid in assessing the effects of such errors on conventional analyses of air-pollution studies.     

Opportunity Theory and Agricultural Crime Victimization*

Abstract A growing body of research lends support to opportunity theory and its variants, but has yet to focus systematically on a number of specific offenses and contexts. Typically, the more crimes and contexts to which a theory applies, the broader its scope and range, respectively, and thus generalizability. In this paper, we focus on agricultural crime victimization— including theft of farm equipment, crops, livestock, and chemicals—an offense that opportunity theory appears well‐situated to explain. Specifically, we examine whether key dimensions of the theory are empirically associated with the likelihood of victimization and also examine factors associated with farmers' use of guardianship measures. In contrast to much previous research, we combine multiple individual‐level measures of these dimensions. We conclude that the theory partially accounts for variation in agricultural crime victimization, depending on the type of crime, and that greater work is needed investigating how key dimensions of opportunity theory should be conceptualized and operationalized in rural contexts. The study's implications for theory and practice are discussed.