Variable selection via the adaptive elastic net: mathematics success of the students in Singapore and Turkey

The quality of education is crucial for its competitiveness in the developing world. International tests are organized at regular intervals to measure the quality of education and to see the place in the ranking of countries. The surveys on these examinations have provided a large number of variables that can be effective on the scores of the tests, including family, teacher, school and course equipment and information communication technologies, etc. The important question is which variables are relevant for the students' achievement in these tests. We investigated the barriers of mathematics success of Turkish students in the TIMSS exam and compared their status with Singaporean students who took part in at top of the ranking in the exam. For this, we employed the adaptive elastic net which is one of the regularized regression methods to dataset and compared their prediction accuracy according to three different alpha levels [0.1; 0.5; 0.9] to determine the model that has high variable selection ability with optimal prediction. The adaptive elastic net with the alpha level [0.9] was selected as superior to others. As the findings, a technology-oriented education system can help to success of the students in Turkey and the countries having similar experiences in international tests.

Main drivers of tobacco consumption among adolescents: the case of Kyrgyzstan

Tobacco smoking among youth is a global concern. Tobacco's dangers and the probability of addiction are often underestimated by young people. Preventing tobacco consumption among youth is critical since tobacco-related illnesses will take away the lives of 250 million young people who continue to smoke into adulthood. Youth are more vulnerable to nicotine and may become addicted to it quicker than adults. Even though they decide to stop in a few years, three out of four teen smokers continue to smoke into adulthood due to nicotine addiction. The main purpose of this study is to investigate tobacco consumption of adolescents in Kyrgyzstan. For this aim, a school-based survey of students aged 13-15 years was utilized. Global Youth Tobacco Survey was conducted in 2019. The questionnaire consists of 56 questions. This survey was conducted in order to get knowledge about adolescents’ attitudes about smoking. In the empirical analysis was employed Heckman selection model. In the light of obtained results it can be concluded that the main drivers of tobacco consumption among adolescents are age, gender, amount of spending money, parental smoking status, among others. The results indicate that tobacco consumption is higher among males. Parents smoking habit leads to a higher probability of an adolescents to become a smoker. The outcomes from this study may provide some insights into the policies implemented to lessen smoking among adolescents.

The behavior of capital structure: evidence from fast calibrated additive quantile regression

In finance, capital structure decisions are crucial due to their impact on the value of a firm. Some theories assert that the value of a firm is irrelevant to those decisions. However, there is a growing literature that criticizes this idea. Those studies are constructed on some modern theories which called trade-off theory, agency cost theory, signaling theory, and pecking order theory. This paper investigates the relationship between optimal capital structure and capital structure components. The annual data gathered from 195 firms traded in Borsa Istanbul for the period 2011-2020 is used. The fast calibrated additive quantile regression approach is chosen because of its superior properties. In that method, there is not a strong assumption about the functional form of the relationships between the dependent variable and the explanatory variables. The results indicate that the relationships between the debt ratios and the capital structure components differ for each quantile and these relations are nonlinear. Furthermore, evidence is found that the relationships might be explained with the modern theories of capital structure.

Demographic variables affecting participation in mammography screening: a cross-sectional study

Breast cancer is one of the most common cancers among women. There are three commonly used diagnostic methods in this cancer type, in which the survival rate can be quite high with early diagnosis. Compared to breast self-examination and clinical examination, mammography stands out as a more accurate diagnostic method. Although there are health policies regarding mammography screening in many countries, mammography screening behavior has not reached the desired level worldwide. In this study, we tried to reveal the demographic factors affecting the frequency of women getting mammograms in Turkey. The frequency of mammography screening was estimated with a generalized logit model using the microdata of TURKSTAT Turkey Health Survey. As a result of the model, it was observed that mammography screening differentiated in different age and income groups. It was determined that the disease status increased the frequency of mammography screening, however, marital status and employment status did not have a significant effect.

Has the gender wage gap narrowed or widened in a decade? Some recent evidence from the Turkish labor market

The principal objective of this study is to determine the variation in the gender wage gap in the last decade of the Turkish labor market and reveal possible factors that drive the wage disparities. Therefore, the data set covers the Household Budget Statistics surveys 2009 and 2018. In order to prevent biased results, the empirical strategy contains the two-stage model estimation and selectivity corrected decomposition approach. The findings claim a widening gender wage gap in a decade. The portion of the gender wage gap resulting from the labor market discrimination tends to increase whereas the wage gap based on the gender differences in characteristics decreases. Despite the decrease, if the female employees had the same characteristics as males, their mean wages would be higher. Moreover, the gender wage gap attributable to gender discrimination in the labor market continues to increase.