Shared frailty model based on reversed hazard rate for left censored data

Frailty models are used in the survival analysis to account for the unobserved heterogeneity in the individual risks to disease and death. To analyze the bivariate data on related survival times (e.g., matched pairs experiments, twin or family data), the shared frailty models were suggested. In this article, we introduce the shared gamma frailty models with the reversed hazard rate. We develop the Bayesian estimation procedure using the Markov chain Monte Carlo (MCMC) technique to estimate the parameters involved in the model. We present a simulation study to compare the true values of the parameters with the estimated values. We apply the model to a real life bivariate survival dataset.     

DOES SOCIAL CAPITAL PROMOTE SAFETY ON THE ROADS?

I present evidence that social capital reduces traffic accidents and related death and injury, using data from a 10‐year panel of 48 U.S. states. The econometric challenge is to distinguish the causal effects of social capital from bias resulting from its correlation with unobservable characteristics by state that influence road risks. I accomplish this by employing snow depth as an instrument, and by restricting attention to summertime accidents. My results show that social capital has a statistically significant and sizable negative effect on crashes, traffic fatalities, serious traffic injuries, and pedestrian fatalities that holds up across a range of specifications. (JEL R41, I18, Z13)     

Consensus in the Marital Dyad: Couples' Perceptions of Contraception,Communication, and Family Life

Abstract

The present study was based on data collected (separately for husbands and wives) from 365 couples to determine levels of consensus on a series of variables related to the family forming process. Following Scheff (1967), consensus was operationalized as both agreement and coorientation in the marital dyad. The data generally indicated low levels of consensus on such variables as contraceptive efficacy, desired family size, child spacing, unwanted pregnancies, communication with spouse, and levels of alienation. The results are discussed within the framework of family planning and effective fertility control.     

The trend of intelligence in certain districts of England

An estimate of the change in intelligence in ten English education authorities during the past 10 years has been made by comparing the scores of complete year groups of 11-year-old children in 1947 with scores made by similar groups in the same test on an earlier occasion. The first test was taken by 31,728 children and the second by 28,505 children, boys and girls in approximately equal numbers.

For boys and girls together there was a fall of 0.0034 point of intelligence quotient per year, which was far from significant. In seven districts where we had separate scores for boys and girls on both occasions there was a significant fall in intelligence quotient of 0.0921 point per year amongst boys and a significant rise of 0.0921 point per year amongst girls.

The adventitious influences which might invalidate a comparison of the two sets of scores have been considered; they probably tend to depress the score at the second test.

A study of sex differences in attainment tests at 11 years and in intelligence tests at 13 years and later suggests that the scores of the boys in 1947 are underestimates of their ability, and that a truer measure of the trend of intelligence amongst the population is represented by the change in the girls' scores.

By assuming a certain parallelism between the present survey and that of the Scottish children, the rise in intelligence quotient of the latter is estimated at 0.0543 point per year.

A significant increase in the dispersion of intelligence test score of both boys and girls during the past 10 years has been recorded.     

Pre-term Foetal Life Times in Scotland

A proportional hazards model was used to evaluate the association between ten categorical covariates and the risk of pre-term delivery for women having their first child and women in subsequent pregnancies. An adaptation of the model for use with grouped survival times made it possible to model foetal life times between 28 and 36 completed weeks of gestation for 67,000 Scottish singleton births in 1981. The use of the model was justified by testing time-dependent effects. For both groups of women age, and a history of abortion, were major factors associated with increased hazard. For women experiencing a second or higher-order birth a history of perinatal death was also associated with substantially increased hazard to the pregnancy.     

A new goodness of fit test for the equality of multinomial cell probabilities versus trend alternatives

In this paper, a new test statistic is presented for testing the null hypothesis of equal multinomial cell probabilities versus various trend alternatives. Exact asymptotic critical values are obtained, The power of the test is compared with several other statistics considered by Choulakian et al (1995), The test is shown to have better power for certain trend alternatives.     

Blood Transfusion in Room 223

How educators handle conflicting views of Populism is important in engaging students in critical thinking.