Risk Homeostasis Theory and Traffic Accident Data

The risk homeostasis theory posits, in essence, that a control mechanism analogous to the thermal homeostatic system in warm-blooded animals tends to keep risk per unit time constant, and, as a consequence, the number of traffic accidents per unit time of driving also tends to remain constant, essentially independent of changes in the traffic safety system. It is the purpose of the present research to examine the validity of this claim using a wide variety of traffic accident data. All the data examined are found to be incompatible with the risk homeostasis theory. The only specific field accident data offered in the literature to support the risk homeostasis theory are found to, in fact, refute the theory. The accident data provide evidence that a rich variety of user responses occur. While it is possible for users to collectively respond in such a way that safety benefits are completely cancelled, such a response is not particularly common; it is certainly not universally occurring, as suggested by the risk homeostasis theory. It is concluded that the risk homeostasis theory should be rejected because there is no convincing evidence supporting it and much evidence refuting it.     

Estimating Fatality Reductions from Increased Safety Belt Use

Fatality reductions from increases in safety belt use are estimated taking into account that drivers who change from being nonusers to being users have lower accident involvement rates than the remaining nonusers, a process referred to as "selective recruitment." Analytical functions are derived which express expected fatality reductions in terms of changes in safety belt use rates from an initial rate. The function parameters are determined by requiring that computed average crash rates for nonusers be 53% higher than the rates for users, a recently determined empirical value. These functions show that, depending on the initial use rate and use rate increase, selective recruitment may increase or decrease expected fatality reductions. However, effects are relatively small, in no case exceeding +/- 5.3%.     

Factors influencing middle and high schools' active parental consent return rates

The authors examined factors influencing the return rates for attempting to collect active parental consent forms from 21,123 students in the 7th through 10th grades in 41 middle and high schools. Overall return rates from middle schools were higher than from high schools. Schools that offered high levels of staff support for collecting consent forms had higher return rates. Procedures where the consent form was attached to a school form that parents had to complete and return to the school yielded the highest return rate. Implications for how researchers can obtain a high parent consent form return rate are discussed.     

Nonverbal cues employed in discriminating between disabled persons and actors

Undergraduate subjects were seen to accurately discriminate between simulating actors and genuinely disabled males confined to wheelchairs. Judgments were based on skill in manipulating the wheelchair, poorer muscular development of the disabled, and on appearance of clothing. Implications for research on the disabled employing actors was discussed.This study was supported by a grant from the York University Faculty of Arts awarded to the first two authors. The project was performed as the third author's Honours thesis. The authors wish to thank all participants for their cooperation and assistance in making this research possible. The authors also wish to thank Gail Kenyon, Coordinator of the Centre for Handicapped Students who helped recruit participants for the videotaping and to Lucie Cantrell, Executive Officer of the York University Counselling and Development Centre who arranged for the use of the Centre's facilities and equipment.     

Do Drivers of Small Cars Take Less Risk in Everyday Driving?

Previously reported observed data on risky everyday driving are brought together and reanalyzed in order to focus on the relation between risky driving and the size of the car being driven, as indicated by car mass. The measures of risky driving include separation between vehicles in heavy freeway traffic and speed on a two lane road. Observed seat belt use provides a third measure of driver risk. Confounding effects arising from the observed association between car mass and driver age are taken into account by segmenting the data into three driver age groups. Driver risk taking is found to increase with increasing car mass for each of these three aspects of everyday driving. The implications of these results with respect to driver fatality rates are discussed in terms of a simple model relating observed risky driving to the likelihood of involvement in a severe crash.     

Speed Mentoring in Teaching and Learning: Young people with experience of the care system mentor social work students

The value of listening and talking to young people with experience of the care system has been recognised as a vital and positive contribution to social work students' learning. A model of co-production was used to develop a series of speed mentoring events whereby social work students placed in local authority children and family settings were mentored by young people with experience of the care system. This tentative review of this small-scale project shares the authors' critical reflections on the value and reliability of this model, for evaluating the outcomes of co-productive mentoring relationships between young people and social work students. The reversal of the power dynamic between student and service user contributed to the unsettling of assumptions about each other and empathy for each other's role. The student authors reflect on learning about the child's experience that has influenced their practice. The mentor authors welcomed the opportunity to participate in the development of ‘young people friendly’ social workers. Suggestions are made as to how this model could be developed to contribute to a more systematic approach to the role of service users in mentoring, advising and contributing to the supervision process of students and social workers.     

Women’s Involvement in Terrorism

Women have had a long history of participating in terrorist activity. This history extends from the earliest modern terrorist group, from the nineteenth century Russian People’s Will to the current wave of suicide bombings carried out by the Chechen Black Widows and the Tamil Tiger’s Birds of Paradise. This article traces the history of female involvement in modern terrorism and then goes on to make a number of generalizations about this experience. Among other things, the writers point out that women have played strong leadership roles in left-wing, revolutionary bands, while these roles have been far fewer with right-wing and racist aggregations. Women have tended to be late-comers to contemporary, religiously-inspired terrorism: Muslim religious authorities first had to endorse their participation.     

Unbiased estimation of a nonlinear function a normal mean with application to measurement err oorf models

Let W be a normal random variable with mean μand known variance σ². Conditions on the function f(·) are given under which there exists an unbiased estimator, f(W), of f(μ) for all real μ. In particular it is shown that f(·) must be an entire function over the complex plane. Infinite series solutions for F(·) are obtained which are shown to be valid under growth conditions of the derivatives, f^k( ·), of f(·). Approximate solutions are given for the cases in which no exact solution exists. The theory is applied to nonlinear measurement-error models as a means of finding unbiased score functions when measurement error is normally distributed. Relative efficiencies comparing the proposed method to the use of conditional scores (Stefanski and Carroll, 1987) are given for the Poisson regression model with canonical link.     

Election Day Registration's Effect on U.S. Voter Turnout

Objective . Early voter registration deadlines make voting more difficult for many American citizens. In an attempt to facilitate voting, several U.S. states now permit registration on election day, at the height of the campaign. This article examines the turnout effects of adopting election day registration (EDR) and other smaller reductions in closing dates. Methods . Primarily using the Current Population Study (1972-1996), we estimate the turnout advantage of EDR for citizens having low, middle, and high socioeconomic status. Results . The elimination of closing dates, through EDR, is predicted to produce about a 7-percentage-point turnout boost in the average state. Those having a high school education and middle incomes are expected to see the largest turnout gains, with the less educated and poorer citizens doing almost as well. No evidence is found to link the implementation of EDR to subsequent changes in the electorate's partisan balance. Conclusions . Even the most dramatic easing of voter registration costs has a modest effect on the total number of voters and little impact on the long-standing skew toward greater representation of those having higher status in the voting electorate of the United States.