A behavioral two‐sex marriage model

In this paper we propose a particular marriage model, i.e., a model for the number of marriages for each age combination as a function of the vectors of the number of single men and women in each age group. The model is based on Dagsvik (2000) where it is demonstrated that a general type of matching behavior imply, under specific assumptions about the distribution of the preferences of the women and men, a convenient expression for the corresponding marriage model.

Data from the Norwegian Population Register for nine years are applied to estimate the model. We subsequently test the hypothesis that, apart from a random “noise”; component, the age‐specific parameters of the model change over time according to a common trend. We find that the hypothesis is not rejected by our data.     

Democracy,civil society and the media in Africa in the Nineties. a discussion of the emergence and relevance of some analytical concepts for the understanding of the situation in Africa

The article argues that the relationship between state and civil society in an African context constitute a dialiectic between a weak state and a weak civil society. The question of the seperation between state and civil society in Africa cannot be understood apart from recent changes in Eastern Europe, with the demise of communism on the one hand, and the rise of neo‐liberalism on the other. Also, the state/society problematic in Africa is linked to the inheritance from the European experience of the nineteenth century, and to the economic restructuring programmes of the 1980s and the 1990s. Civil society in Africa is seen as constituted by a variety of social movements which through their forms of communication tap in on and recreate existing and new collective identities. The article gives special attention to the case in Zimbabwe and the role of the media and civil society there.     

Paradoxes and Improvements in Interval Estimation

Cases where confidence sets are empty or include every possible parameter value are an embarrassment to standard theory and difficult to explain to students. To alleviate this problem, and as a convenient way of showing how each parameter value is ranked in view of the data, we propose to plot the confidence set for each possible level, called a confidence curve. Different confidence procedures then lead to different confidence curves. In standard situations involving distributions with a monotone likelihood ratio, we suggest using the confidence curve based on Spjøtvoll's acceptability function. For discrete distributions, this leads to an improvement over usual “exact” confidence intervals.     

Concordance of Carcinogenic Response between Rodent Species: Potency Dependence and Potential Underestimation

The use of average qualitative concordance between two bioassay endpoints is considered, with emphasis directed at agreement between rats and mice from results of long-term carcinogenicity studies. It is noted that concordance varies as a function of the underlying potency or toxicity of the chemicals over which the averaging is performed. Thus, the averaging process dilutes large observed concordances from potent chemicals, and possibly inflates lower observed concordances from weakly active chemicals. Stratification over some measure of potency is suggested as a method for taking these effects into account. Statistical simulations of concordance analyses limited to low-potency ranges are employed to examine the concordance measure in greater detail. It is seen that at low potencies, observed concordance is consistently underestimated, reaching maximum levels of only about 80%.     

Statistical Modeling of Animal Bioassay Data with Variable Dosing Regimens: Example—Vinyl Chloride

We consider animal bioassay experiments with variable dosing regimens in which groups of animals are dosed beginning at different ages and for varying durations. Two response models are discussed and then applied to data from an experiment on vinyl chloride exposure of F-344 rats, B6C3F1 and Swiss CD-1 mice, and Syrian Golden hamsters. The multistage model of Armitage and Doll, as extended by Whittemore, Day and Brown, and Crump and Howe, is used to estimate the dose effect on the ordered stages of tumor development. The data for all endpoints and species/strains examined consistently indicate a predominant effect on the first stage, suggesting that vinyl chloride is primarily a tumor initiator. This is consistent with evidence from two-stage experiments on this chemical. The second response model, new to this article, adjusts for survival nonparametrically. It is used to test for an age difference in susceptibility, to evaluate alternative exposure durations, and to compare the effectiveness of alternative dosing regimens for detecting carcinogenicity.     

Self‐financing Unemployment Insurance and Bargaining Structure

Abstract. This study examines how the size of trade unions relative to the labor force impacts on the desirability of different organizational forms of self‐financing unemployment insurance (UI). For this purpose, we compare the outcome of a model with a uniform payroll tax to a model where workers pay taxes according to their systematic risk of unemployment. Our results highlight the importance of the bargaining structure for the assessment of a particular UI scheme. Most importantly, it depends on the relative size of the unions whether efficiency favors a uniform or a differentiated UI scheme.     

An empirical real-world study of losses disguised as wins in electronic gaming machines

Losses disguised as wins (LDWs) appear to reinforce gambling persistence. However, little research has examined this phenomenon with real gamblers in natural gambling settings. We aimed to examine the relationship between within-session outcome size and subsequent gambling persistence. Account-based gambling data of individuals playing LDW games over a randomly selected day (2,035,339 bets made by 8636 individuals) was examined. We used a logistic mixed effects model to examine the relationship between the outcome of the previous bet (loss, LDW and real wins) and the odds of continuing betting in a game session. The odds of continuing betting in a game session were positively associated with the outcome of the previous bet. Compared to LDWs, losses lowered the odds of continuing a game session. In contrast, real wins implied greater odds of continuing a game session compared to LDWs. It is concluded that LDWs increase the likelihood of continuing betting compared to losses, but decrease the likelihood of continuing to gamble compared to real wins. As LDWs increase the number of bets made within a gambling session, and hence within-session gambling persistence, LDWs may potentially play an etiological role in the development of gambling problems over time.     

Measuring exposure to bullying and harassment at work: Validity,factor structure and psychometric properties of the Negative Acts Questionnaire-Revised

Abstract

This study investigates the psychometric properties, factor structure and validity of the revised Negative Acts Questionnaire-Revised (NAQ-R), an instrument designed to measure exposure to bullying in the workplace. By reanalyzing data based on a heterogeneous sample of 5288 UK employees, the results show that the 22-item instrument has a high internal stability, with three underlying factors: personal bullying, work-related bullying and physically intimidating forms of bullying, although the instrument may also be used as a single factor measure. Criterion validity was explored by relating the scores on the NAQ-R to a single-item measure of perceived victimization from bullying, showing high correlations with both the total NAQ-R and scores on the three factors. Targets of bullying scored significantly higher on all 22 items compared to non-targets. The NAQ-R correlated as expected with measures of mental health, psychosocial work environment and leadership, indicating a good construct validity of the instrument. Furthermore, a latent class cluster (LCC) analysis showed that the instrument may be used to differentiate between groups of employees with different levels of exposure to bullying, ranging from infrequent exposure to incivility at work to severe victimization from bullying and harassment. The more commonly used operational criteria can also be used to detect targets of bullying. Hence, the NAQ-R is proposed as a standardized and valid instrument for the measurement of workplace bullying.     

A pilot study of CBT versus escitalopram combined with CBT in the treatment of pathological gamblers

We conducted a randomised controlled trial pilot study (N = 30) with two treatment groups: (1) Manualised cognitive behavioural therapy (CBT) (n = 15) and (2) escitalopram combined with CBT (n = 15). Treatment was administered individually and the CBT included weekly sessions for eight consecutive weeks. The treatment with escitalopram lasted for a minimum of 16 weeks (20 mg/day), with an optional continuation for a 6-month follow-up period. Repeated measures ANOVA with modified intent-to-treat analyses were conducted. Results showed significant time effects on all measures for both treatment conditions, although no significant group or time × group effects. The results indicated that both treatments were effective in the short term (effect sizes (ES) ranging from 0.45 to 0.91 for the CBT group and 0.27 to 0.72 for the escitalopram+CBT group), and that adding CBT to escitalopram had no additional statistically significant effect (between-group ES of 0.11 and 0.29 for primary outcome measures at 16-weeks post-treatment).     

Corrigenda: Confidence curves and improved exact confidence intervals for discrete distribution

Due to a typesetting error, the second sentence in the proof of Theorem 2 on page 792 was garbled. It should read, “It suffices to consider confidence intervals when x = 1 is observed, although this phenomenon always occurs if the rejection regions involve probabilities from both tails.”