Effect of outliers on the GFI quality adjustment index in structural equation model and proposal of alternative indices

This work is intended to suggest modifications in the construction of the GFI index using robust methods for estimating the unrestricted sample covariance matrix, leading to new indices called GFI_(MCD) and GFI_(MVE). The validation of this proposal was made using Monte Carlo simulation methods, considering differences between the unrestricted sample covariance matrix and those imposed by the structural model, and different numbers of outliers generated by distributions with deviations from symmetry and excess kurtosis. It was concluded that for larger samples size (n ? 100), given that the outliers are from distributions that are symmetrical, the GFI_(MCD) and GFI_(MVE) present similar results, including samples with high percentages of outliers.     

Demographic components of growth in white,black, and Puerto Rican female-headed families: Comparison of the Cutright and Ross/Sawhill methodologies

This study examines the methodological differences between Cutright's (1974, Journal of Marriage and the Family36, 714–721) and Ross and Sawhill's (1975, Time of Transition: The Growth of Families Headed by Women. The Urban Institute, Washington, D.C.) analyses of demographic components of growth in the number of female-headed families and replicates their procedures within a comparable time/age framework in order to resolve their contradictory findings. The analysis suggests that while changes in living arrangements and population are the two major factors accounting for changes in the number of White female-headed families between 1940 and 1970, marital instability is the major factor responsible for the increase in the number of White female-headed families between 1960 and 1970. Cutright's analysis of long-term changes for nonwhites is debatable. The relative importance of demographic factors in explaining the absolute increase in female-headed families between 1960 and 1970 clearly varies by ethnic/racial group.     

Influence analysis in skew-Birnbaum–Saunders regression models and applications

In this paper, we propose a method to assess influence in skew-Birnbaum–Saunders regression models, which are an extension based on the skew-normal distribution of the usual Birnbaum–Saunders (BS) regression model. An interesting characteristic that the new regression model has is the capacity of predicting extreme percentiles, which is not possible with the BS model. In addition, since the observed likelihood function associated with the new regression model is more complex than that from the usual model, we facilitate the parameter estimation using a type-EM algorithm. Moreover, we employ influence diagnostic tools that considers this algorithm. Finally, a numerical illustration includes a brief simulation study and an analysis of real data in order to show the proposed methodology.     

Cure rate survival models with missing covariates: a simulation study

In this paper we study the cure rate survival model involving a competitive risk structure with missing categorical covariates. A parametric distribution that can be written as a sequence of one-dimensional conditional distributions is specified for the missing covariates. We consider the missing data at random situation so that the missing covariates may depend only on the observed ones. Parameter estimates are obtained by using the EM algorithm via the method of weights. Extensive simulation studies are conducted and reported to compare estimates efficiency with and without missing data. As expected, the estimation approach taking into consideration the missing covariates presents much better efficiency in terms of mean square errors than the complete case situation. Effects of increasing cured fraction and censored observations are also reported. We demonstrate the proposed methodology with two real data sets. One involved the length of time to obtain a BS degree in Statistics, and another about the time to breast cancer recurrence.     

Measuring Love: Sexual Minority Male Youths' Ideal Romantic Characteristics

Research examining how sexual minorities characterize love within same-sex relationships is scarce. In this study, we examined the validity of Sternberg's Triangular Theory of Love in a sample of sexual minority male youth (N = 447). To test the adequacy of the theory for our population, we examined the psychometric properties of the Triadic Love Scale (TLS) and tested whether the three underlying constructs of the theory (Intimacy, Passion, and Commitment) emerged when participants were asked to consider their ideal relationship with another man. Using confirmatory factor analysis (CFA), we found support for the three-factor solution to characterize sexual minority male youths' ideal romantic relationship, after minimizing item cross-loadings and adapting the content of the Passion subscale. We discuss the implications of our findings regarding the measurement of the TLS among sexual minority male youth and propose ways to enhance its measurement in future research.     

Son preference and the one child policy in China: 1979–1988

Using data from the Two-Per-Thousand National Fertility Survey, this research analyzes how son preference, a deep-rooted cultural norm for more than two thousand years, affects compliance with China's one child population policy for women at risk during the period of 1979 to 1988. Four events after the first live birth are used to evaluate compliance with the policy: (1) certificate acceptance (an indicator of future fertility intention); (2) the use of contraceptives (an indicator of intention to prevent a subsequent pregnancy); (3) the occurrence of a pregnancy subsequent to the first live birth (a potential violation of the one child policy), and (4) among those pregnant, the likelihood of an abortion (an indicator of compliance by preventing a second live birth). It is found that son preference is still prevalent in China. Although the effect of son preference is not the most important, urbanization, education, and occupation have not fundamentally changed its influence on women's compliance. In addition, the effect of son preference on the compliance is not altered by government control. Preference for sons continues to be a factor discouraging the compliance with the one child policy.This article is based on a paper presented at the annual meeting of the Population Association of America, 1–4 April 1993, Cincinnati, OH, USA.