Son Preference and Fertility Decisions: Evidence From Spatiotemporal Variation in Korea.

Using Korean data, this study investigates whether son-favoring ideas or the preference for sons affect fertility decisions. Son-favoring fertility behavior in Korea is of interest because the sex ratio at birth has recovered to a natural level after having been very skewed. To isolate the effects of the preference for sons from the effects of the surrounding environment, we compare the fertility behavior of individuals living in the same region but who were born in different regions or years. Exploiting the male-female gap in educational achievement at the parents' time and place of birth as exogenous variation in the 2000 Census Korea 2% sample, we find that the strength of son preference formed at an early age is associated with the strength of son-favoring fertility behavior as adults. Our results indicate that parents are more likely to have a third child if they happen to have only daughters as their first two children. More importantly, this tendency is stronger if parents were born in a spatiotemporal region with more skewed gender gap in educational investment. These findings are robust against various alternative specifications, including endogenous migration issues.

Gender Wage Gap Accounting: The Role of Selection Bias.

Mulligan and Rubinstein (2008) (MR) argued that changing selection of working females on unobservable characteristics, from negative in the 1970s to positive in the 1990s, accounted for nearly the entire closing of the gender wage gap. We argue that their female wage equation estimates are inconsistent. Correcting this error substantially weakens the role of the rising selection bias (39 % versus 78 %) and strengthens the contribution of declining discrimination (42 % versus 7 %). Our findings resonate better with related literature. We also explain why our finding of positive selection in the 1970s provides additional support for MR's main hypothesis that an exogenous rise in the market value of unobservable characteristics contributed to the closing of the gender gap.

Neoadjuvant chemotherapy in advanced ovarian cancer: optimal patient selection and response evaluation.

Epithelial ovarian cancer (EOC) is the leading cause of death from gynecologic malignancy and is the seventh most common cancer among women worldwide. The primary debulking surgery (PDS) followed by adjuvant chemotherapy (ACT) is a standard treatment of advanced EOC. However, there are still several limitations, such as high recurrence rate and subsequent chemoresistance. To date, many studies have reported that neoadjuvant chemotherapy (NACT) followed by interval debulking surgery (IDS) shows non-inferior survival outcome and is associated with less postoperative morbidity compared with PDS. Therefore, NACT-IDS might be an alternative treatment strategy in advanced EOC. Nevertheless, the efficacy of NACT-IDS and selection of patients who would gain benefit from NACT-IDS are still on debate. To date, several studies have been conducted to predict the response of NACT using various methods, such as imaging studies and molecular biology techniques. In this article, the optimal indications for NACT using various methods will be discussed.

Distribution-free estimation of zero-inflated models with unobserved heterogeneity.

This paper presents a quasi-conditional likelihood method for the consistent estimation of both continuous and count data models with excess zeros and unobserved individual heterogeneity when the true data generating process is unknown. Monte Carlo simulation studies show that our zero-inflated quasi-conditional maximum likelihood (ZI-QCML) estimator outperforms other methods and is robust to distributional misspecifications. We apply the ZI-QCML estimator to analyze the frequency of doctor visits.

Coresidence with husband's parents, labor supply, and duration to first birth.

This article investigates the time to first birth, treating coresidence with husband's parents and labor supply as endogenous and using representative data on Taiwanese married women born during 1933-1968. We use a full-information maximum likelihood estimator for a duration model with endogenous binary variables. Results controlling for endogeneity suggest that both coresidence and working are associated with a delay in childbearing, reversing the effect of coresidence on the timing of first birth but not that of working. Women in earlier cohorts tend to choose coresidency and not working, and an increasing number of women from later cohorts choose to do both or to work only.