Handling Missing Values in Longitudinal Panel Data With Multiple Imputation

This article offers an applied review of key issues and methods for the analysis of longitudinal panel data in the presence of missing values. The authors consider the unique challenges associated with attrition (survey dropout), incomplete repeated measures, and unknown observations of time. Using simulated data based on 4 waves of the Marital Instability Over the Life Course Study (n = 2,034), they applied a fixed effect regression model and an event‐history analysis with time‐varying covariates. They then compared results for analyses with nonimputed missing data and with imputed data both in long and in wide structures. Imputation produced improved estimates in the event‐history analysis but only modest improvements in the estimates and standard errors of the fixed effects analysis. Factors responsible for differences in the value of imputation are examined, and recommendations for handling missing values in panel data are presented.     

“THE WAR FOR THE FARE”: HOW DRIVER COMPENSATION AFFECTS BUS SYSTEM PERFORMANCE

Prior to 2007, two systems of bus driver compensation coexisted in Santiago, Chile: one paid drivers per passenger transported, while the other paid a fixed wage. Per‐passenger drivers engaged in “The War for the Fare,” altering their driving patterns to compete for passengers. Examining these systems on similar routes in Santiago, we observed two key findings. Compared with the fixed‐wage system, the per‐passenger system leads to (1) 13% shorter passenger wait times, via reduced bunching of buses and (2) 67% more accidents per kilometer driven, via more aggressive driving. We discuss implications for the design of incentives in public transit. (JEL L92, M52, R41)     

The Challenges in Developing an Online Applied Statistics Program: Lessons Learned at Penn State University

Numerous professional fields have an increasing need for individuals trained in statistics and other quantitative analysis techniques. Today there exists great potential to fulfill this need by providing opportunities through online learning. However, to provide a high-quality education for returning adult professionals seeking advanced degrees in applied statistics online, many challenges need to be overcome. Based on our experience developing Penn State University’s online program in applied statistics, we discuss the evolution of the program’s curriculum, recruitment and development of online faculty, and meeting the requirements of students as important areas that require consideration in the development of an online program. We also highlight program evaluation strategies employed to ensure innovation and improvement in online education as cornerstones to a program’s success.     

Fragmented identities, frustrated politics: transsexuals, lesbians and 'queer'

This paper seeks to explore the complex position transsexualism has in relation to a range of personal identities and identity politics. In recent years there has been considerable debate over 'borderline identities' particularly between lesbians, transgenderists, and FTM and MTF transsexuals who transgress the identity category 'lesbian.'2 Stronger political affiliations between transsexuals, lesbians and feminists are argued for, and a greater recognition of the futility in attempting to demarcate the infinitely blurred ontological boundaries between 'sex,' gender and sexuality. Rather, we should focus on 'issue' based politics that challenge heterosexist and normative gender epistemologies and practices that restrict non-conformist subjectivities.     

Public Opinion and Dynamic Representation in the American States: The Case of Environmental Attitudes*

Objective. We investigate causal processes linking environmental conditions, attitudes, and policies in the American states: Is public opinion about ecology shaped by environmental conditions? Are state policymakers responsive to environmental opinions? Does public opinion respond to policy adoption? Methods. Using public opinion data from the DDB Worldwide Life Style Survey to measure aggregate state attitudes about the environment, as well as measures of water quality and policy intervention, we capture the dynamics of representation in the American states on the environment during the late 1980s and early 1990s. Results. Our findings support a thermostatic model of representation—state environmental opinions are influenced by environmental conditions and are responsive to policy outputs alongside improved environmental conditions. Conclusions. This model of the opinion‐policy linkage refines our understanding of representation and focuses us not just on the passage of public policy to address public desires, but the effectiveness of that policy as well.     

Food packaging 1974–1984

The author argues that it is clear that the manufacturers of most food products now have a bewildering array of alternative forms of packaging from which to choose. Due to pressure on profit margins, they will look for those systems that will be the cheapest having regard to many technical, commercial, legal and ecological factors. There will often be many different answers to any one packaging problem and all will be right to some extent! And not one is likely to satisfy every need!     

Acculturation,Ethnicity, and Air Pollution Perceptions

A globalizing world increases immigration between nations, raising the question of how acculturation (or its lack) of immigrants and their descendants to host societies affects risk perceptions. A survey of Paterson, New Jersey, residents tested acculturation's associations with attitudes to air pollution and its management, and knowledge of and self‐reported behaviors concerning air pollution. Linguistic and temporal proxy measures for acculturation were independent variables along with ethnicity, plus controls for gender, age, education, and income in multivariate analyses. About one‐fifth of contrasts between non‐Hispanic whites, non‐Hispanic blacks, English‐interviewed Hispanics, and Spanish‐interviewed Hispanics were statistically significant (Bonferroni‐corrected) and of medium or higher affect size, with most featuring the Spanish‐interviewed Hispanics. Knowledge variables featured the most significant differences. Specifically, Spanish‐interviewed Hispanics reported less concern, familiarity with pollution, recognition of high pollution, and vigorous outdoor activity, and greater belief that government overregulates pollution than English‐interviewed Hispanics (and than the other two groups on most of these variables too). English‐interviewed Hispanics did not differ from non‐Hispanic whites, but did on several variables from non‐Hispanic blacks. Temporal proxies of acculturation among the foreign‐born were far less significant, but concern and familiarity with air pollution increased with time spent in the United States, while belief in overregulation and a positive trend in New Jersey pollution increased with time in the nation of origin. Implications of these acculturation and ethnicity findings for risk perception/communication research and practice are discussed.     

Bayesian Binomial Regression: Predicting Survival at a Trauma Center

Standard methods for analyzing binomial regression data rely on asymptotic inferences. Bayesian methods can be performed using simple computations, and they apply for any sample size. We provide a relatively complete discussion of Bayesian inferences for binomial regression with emphasis on inferences for the probability of “success.” Furthermore, we illustrate diagnostic tools, perform model selection among nonnested models, and examine the sensitivity of the Bayesian methods.