Feinian Chen

Improper solutions in structural equation models: Causes, consequences, and strategies

In this article, the authors examine the most common type of improper solutions: zero or negative error variances. They address the causes of, consequences of, and strategies to handle these issues. Several hypotheses are evaluated using Monte Carlo simulation models, including two structural equation models with several misspecifications of each model. Results suggested several unique findings. First, increasing numbers of omitted paths in the measurement model were associated with decreasing numbers of improper solutions. Second, bias in the parameter estimates was higher in samples with improper solutions than in samples including only proper solutions. Third, investigations of the consequences of using constrained estimates in the presence of improper solutions indicated that inequality constraints helped some samples achieve convergence. Finally, the use of confidence intervals as well as four other proposed tests yielded similar results when testing whether the error variance was greater than or equal to zero.

Monte Carlo Experiments: Design and Implementation.

The use of Monte Carlo simulations for the empirical assessment of statistical estimators is becoming more common in structural equation modeling research. Yet, there is little guidance for the researcher interested in using the technique. In this article we illustrate both the design and implementation of Monte Carlo simulations. We present 9 steps in planning and performing a Monte Carlo analysis: (1) developing a theoretically derived research question of interest, (2) creating a valid model, (3) designing specific experimental conditions, (4) choosing values of population parameters, (5) choosing an appropriate software package, (6) executing the simulations, (7) file storage, (8) troubleshooting and verification, and (9) summarizing results. Throughout the article, we use as a running example a Monte Carlo simulation that we performed to illustrate many of the relevant points with concrete information and detail.

Social Change and Socioeconomic Disparities in Health over the Life Course in China: A Cohort Analysis

This article examines social stratification in individual health trajectories for multiple cohorts in the context of China’s dramatically changing macro-social environment. Using data from the China Health and Nutrition Survey, we find significant socioeconomic status (SES) differences in the mean level of health and that these SES differentials generally diverge over the life course. We also find strong cohort variations in SES disparities in the mean levels of health and health trajectories. The effect of education on health slightly decreases across successive cohorts. By contrast, the income gap in health trajectories diverges for earlier cohorts but converges for most recent cohorts. Both effects are more pronounced in rural areas. Given that these cohort effects are opposite those reported in recent U.S. studies, we discuss China’s unique social, economic, and political settings. We highlight the association between SES and health behaviors, China’s stage of epidemiologic transition, and the changing power of the state government and its implications for health care.This article examines social stratification in individual health trajectories for multiple cohorts in the context of Chinas dramatically changing macro-social environment. Using data from the China Health and Nutrition Survey, we find significant socioeconomic status (SES) differences in the mean level of health and that these SES differentials generally diverge over the life course. We also find strong cohort variations in SES disparities in the mean levels of health and health trajectories. The effect of education on health slightly decreases across successive cohorts. By contrast, the income gap in health trajectories diverges for earlier cohorts but converges for most recent cohorts. Both effects are more pronounced in rural areas. Given that these cohort effects are opposite those reported in recent U.S. studies, we discuss Chinas unique social, economic, and political settings. We highlight the association between SES and health behaviors, Chinas stage of epidemiologic transition, and the changing power of the state government and its implications for health care.

The noncentral chi-square distribution in misspecified structural equation models : Finite sample results from a Monte Carlo simulation

The noncentral chi-square distribution plays a key role in structural equation modeling (SEM). The likelihood ratio test statistic that accompanies virtually all SEMs asymptotically follows a noncentral chi-square under certain assumptions relating to misspecification and multivariate distribution. Many scholars use the noncentral chi-square distribution in the construction of fit indices, such as Steiger and Linds (1980) Root Mean Square Error of Approximation (RMSEA) or the family of baseline fit indices (e.g., RNI, CFI), and for the computation of statistical power for model hypothesis testing. Despite this wide use, surprisingly little is known about the extent to which the test statistic follows a noncentral chi-square in applied research. Our study examines several hypotheses about the suitability of the noncentral chi-square distribution for the usual SEM test statistic under conditions commonly encountered in practice. We designed Monte Carlo computer simulation experiments to empirically test these research hypotheses. Our experimental conditions included seven sample sizes ranging from 50 to 1000, and three distinct model types, each with five specifications ranging from a correct model to the severely misspecified uncorrelated baseline model. In general, we found that for models with small to moderate misspecification, the noncentral chi-square distribution is well approximated when the sample size is large (e.g., greater than 200), but there was evidence of bias in both mean and variance in smaller samples. A key finding was that the test statistics for the uncorrelated variable baseline model did not follow the noncentral chi-square distribution for any model type across any sample size. We discuss the implications of our findings for the SEM fit indices and power estimation procedures that are based on the noncentral chi-square distribution as well as potential directions for future research.

Latent Variable Models Under Misspecification: Two-Stage Least Squares (2SLS) and Maximum Likelihood (ML) Estimators

This article compares maximum likelihood (ML) estimation to three variants of two-stage least squares (2SLS) estimation in structural equation models. The authors use models that are both correctly and incorrectly specified. Simulated data are used to assess bias, efficiency, and accuracy of hypothesis tests. Generally, 2SLS with reduced sets of instrumental variables performs similarly to ML when models are correctly specified. Under correct specification, both estimators have little bias except at the smallest sample sizes and are approximately equally efficient. As predicted, when models are incorrectly specified, 2SLS generally performs better, with less bias and more accurate hypothesis tests. Unless a researcher has tremendous confidence in the correctness of his or her model, these results suggest that a 2SLS estimator should be considered.

Employment Transitions and the Household Division of Labor in China

Highlighting one aspect of the economic transition in China (industrialization), this article focuses on how a change in employment from an agricultural to a non-agricultural job could change the household division of labor. Longitudinal analysis of data from the China Health and Nutrition Survey showed that such job shifts affected the household division of labor in different directions and magnitude, depending upon which spouse changed jobs. If the husband changed from an agricultural to a non-agricultural job, he cut back on housework, thereby increasing the difference in the number of hours of housework each spouse performed. If the wife experienced such a job change, the reduction in her housework hours was twice that of her husbands, reducing the difference between their shares of household duties.

Living Arrangements and Health of Older Adults in India

OBJECTIVES We investigate the association between the multigenerational household context and health of older adults in India, taking into account potential selection effects. METHODS Using data from the India Human Development Survey (2004-05), a nationally representative multitopic data set, we employed a two-step analytical strategy--logistic regression followed by propensity score stratification method--to model the effect of contrasting living arrangement types on short-term illness. RESULTS Overall, older adults living in multigenerational households have the lowest levels of short-term illness. Among them, those who live with their spouse, adult children, and young grandchildren experience the highest health gains. Health advantage diminishes when older adults live only with a spouse and adult children, and further diminishes when they live only with their spouse. Solitary living is associated with the highest likelihood of short-term morbidity. Good health is also shown to be associated with household wealth, gender, household size, and urban residence. DISCUSSION Our study demonstrates that multigenerational households--the traditional and the most dominant form of living arrangement in India--have protective health benefits for older adults, while taking into account potential selection mechanisms. On Contrary to some epidemiological studies, we do not find any elevated risk of exposure to short-term illness, when older adults are living in households with young grandchildren.

Family Life Course Transitions and Rural Household Economy During China's Market Reform

This article investigates the effect of family life course transitions on labor allocation strategies in rural Chinese households. We highlight three types of economic activity that involve reallocation of household labor oriented toward a more diversified, nonfarm rural economy: involvement in wage employment, household entrepreneurship, and/or multiple activities that span economic sectors. With the use of data from the China Health and Nutrition Survey (CHNS 1997, 2000, and 2004), our longitudinal analyses of rural household economic activity point to the significance of household demography, life course transitions, and local economic structures as factors facilitating household labor reallocation. First, as expected, a relatively youthful household structure is conducive to innovative economic behavior. Second, household entrances and exits are significant, but their impacts are not equal. Life events such as births, deaths, marriage, or leaving home for school or employment affect household economy in distinctive ways. Finally, the reallocations of household labor undertaken by households are shaped by local economic structures: in particular, the extent of village-level entrepreneurial activity, off-farm employment, and out-migration.

Psychological well-being of the institutionalized and community-residing oldest old in China: The role of children

Studies have shown that institutionalized older adults have worse psychological health than their community-residing counterparts. However, much less is known about this association in developing countries such as China with a rapidly aging population and a short history of institutional care. This article investigates the role of children in differences in psychological well-being between institutionalized and community-residing oldest-old adults in China. Using national data from the 1998, 2000, and 2002 waves of the Chinese Longitudinal Healthy Longevity Survey, results show that the institutionalized have significantly better psychological health-measured by positive affect, loneliness, and quality of life-than those living in the community. Furthermore, we find that the associations are moderated by child-related factors (number of children, proximity, and visits) and strengthened for the three measures of psychological well-being after adjustments for socioeconomic factors, social support, health behaviors, and health status. The results underscore the importance of family dynamics for the psychological health of the institutionalized population in a historically family-care oriented society.

Family division in China’s transitional economy

Using a longitudinal data-set (the China Health and Nutrition Survey) we explored the effect of various economic factors, including household wealth, employment sector, and involvement in a household business on the division of extended families in Chinas transitional economy. Results from event history analyses suggest that these economic factors act as either a dividing or a unifying force on the extended family. Household wealth reduces the risk of family division, but the effect is weaker for families in which parents have upper secondary education. In addition, an extended family is more likely to divide when married children work in the state sector. Further, the probability of family division is higher in families where daughters-in-law work in the state sector than in those with sons in this sector. Finally, involvement in a household business for married children increases family stability.