Are elderly drivers a road hazard?: Problem definition and political impact

Elderly drivers are increasing in number and some statistics show they are more likely to be involved in fatal accidents than all other age groups but those under 25. States have attempted to address the problem in various ways, but very few have required mandatory retesting at license renewal for those beyond a particular age. Why have so few states chosen to act? The key is how the issue is framed for the public and decision makers. Several phases of problem definition are explored to explain the political dynamics of the older driver issue: incidence, causality, severity, crisis labeling, problem population characteristics, and linkage of values to the issue and solutions. Based upon this analysis, it is not surprising that elder interest groups have been successful in containing policy initiatives designed to restrict elderly driving.     

The foundations of econometrics-are there any

The conclusions of alogically consistent economic theory which strictly adheres to Aristotle's axioms of logic are factually true if its sufficient conditions are all factually true. Alternatively, if a conclusion of such a theory is false, then at- least one of its assumptions is false. Unfortunately, the factual truth of sufficient conditions cannot be established because the problem of induction i s impossible t o solve. It is algo true that the falsity of a conclusion cannot be established in the presence of uncertainty. While the philosophy of instrumentalism applied to sufficient and logically consistent explanations may provide useful solutions to immediate practical problems, the principles of simplicity, parsimony and profligacy--all of them requiring conditional deductive arguments--are useless as criteria for model choice.     

The Use of Lay Assessors

This paper reports on some findings from a research study conductedby the authors for the Commission for Social Care Inspection.It examines the reasons for the involvement of lay assessorsand perceptions of the effectiveness of lay assessors in specificregulatory functions.     

Stages of Mentoring: An Analysis of an Intervention for Pregnant and Parenting Adolescents

A qualitative analysis of 51 matches between volunteer mentors and pregnant adolescents is discussed in terms of problems that occurred and reasons relating to early termination of the match. In each of three stages of the relationship, different issues related to the behavior and interpersonal process between members of the match created problems. In stage one, the mentors had difficulty establishing the match when there was avoidance, distrust, and testing behavior on the part of the mentee. Fear of intimacy and rejection seemed to underlie these relationship difficulties. In stage two, which encompassed the birth of the adolescent’s child, conflict occurred when mentees’ demands overwhelmed the mentors. In the third stage, difficulties discussing termination or continuation of the relationship led to disengagement and less frequent contact. Recommendations are provided to help mentors and mentees navigate the problems in each of these stages.     

Diesel Engine Exhaust and Lung Cancer Mortality: Time‐Related Factors in Exposure and Risk

To develop a quantitative exposure‐response relationship between concentrations and durations of inhaled diesel engine exhaust (DEE) and increases in lung cancer risks, we examined the role of temporal factors in modifying the estimated effects of exposure to DEE on lung cancer mortality and characterized risk by mine type in the Diesel Exhaust in Miners Study (DEMS) cohort, which followed 12,315 workers through December 1997. We analyzed the data using parametric functions based on concepts of multistage carcinogenesis to directly estimate the hazard functions associated with estimated exposure to a surrogate marker of DEE, respirable elemental carbon (REC). The REC‐associated risk of lung cancer mortality in DEMS is driven by increased risk in only one of four mine types (limestone), with statistically significant heterogeneity by mine type and no significant exposure‐response relationship after removal of the limestone mine workers. Temporal factors, such as duration of exposure, play an important role in determining the risk of lung cancer mortality following exposure to REC, and the relative risk declines after exposure to REC stops. There is evidence of effect modification of risk by attained age. The modifying impact of temporal factors and effect modification by age should be addressed in any quantitative risk assessment (QRA) of DEE. Until there is a better understanding of why the risk appears to be confined to a single mine type, data from DEMS cannot reliably be used for QRA.     

Reanalysis of the DEMS Nested Case‐Control Study of Lung Cancer and Diesel Exhaust: Suitability for Quantitative Risk Assessment

The International Agency for Research on Cancer (IARC) in 2012 upgraded its hazard characterization of diesel engine exhaust (DEE) to “carcinogenic to humans.” The Diesel Exhaust in Miners Study (DEMS) cohort and nested case‐control studies of lung cancer mortality in eight U.S. nonmetal mines were influential in IARC's determination. We conducted a reanalysis of the DEMS case‐control data to evaluate its suitability for quantitative risk assessment (QRA). Our reanalysis used conditional logistic regression and adjusted for cigarette smoking in a manner similar to the original DEMS analysis. However, we included additional estimates of DEE exposure and adjustment for radon exposure. In addition to applying three DEE exposure estimates developed by DEMS, we applied six alternative estimates. Without adjusting for radon, our results were similar to those in the original DEMS analysis: all but one of the nine DEE exposure estimates showed evidence of an association between DEE exposure and lung cancer mortality, with trend slopes differing only by about a factor of two. When exposure to radon was adjusted, the evidence for a DEE effect was greatly diminished, but was still present in some analyses that utilized the three original DEMS DEE exposure estimates. A DEE effect was not observed when the six alternative DEE exposure estimates were utilized and radon was adjusted. No consistent evidence of a DEE effect was found among miners who worked only underground. This article highlights some issues that should be addressed in any use of the DEMS data in developing a QRA for DEE.