Innovation, Entry into Multiple Markets and Unobserved Heterogeneity

Author(s):  
Ganna Pogrebna ◽  
Christian Schade
2008 ◽  
Vol 29 (3) ◽  
pp. 134-147 ◽  
Author(s):  
Manuel C. Voelkle ◽  
Nicolas Sander

University dropout is a politically and economically important factor. While a number of studies address this issue cross-sectionally by analyzing different cohorts, or retrospectively via questionnaires, few of them are truly longitudinal and focus on the individual as the unit of interest. In contrast to these studies, an individual differences perspective is adopted in the present paper. For this purpose, a hands-on introduction to a recently proposed structural equation (SEM) approach to discrete-time survival analysis is provided ( Muthén & Masyn, 2005 ). In a next step, a prospective study with N = 1096 students, observed across four semesters, is introduced. As expected, average university grade proved to be an important predictor of future dropout, while high-school grade-point average (GPA) yielded no incremental predictive validity but was completely mediated by university grade. Accounting for unobserved heterogeneity, three latent classes could be identified with differential predictor-criterion relations, suggesting the need to pay closer attention to the composition of the student population.


2017 ◽  
Vol 14 (3) ◽  
pp. 331-342 ◽  
Author(s):  
Thomas John Cooke ◽  
Ian Shuttleworth

It is widely presumed that information and communication technologies, or ICTs, enable migration in several ways; primarily by reducing the costs of migration. However, a reconsideration of the relationship between ICTs and migration suggests that ICTs may just as well hinder migration; primarily by reducing the costs of not moving.  Using data from the US Panel Study of Income Dynamics, models that control for sources of observed and unobserved heterogeneity indicate a strong negative effect of ICT use on inter-state migration within the United States. These results help to explain the long-term decline in internal migration within the United States.


Author(s):  
Miao Yu ◽  
Jinxing Shen ◽  
Changxi Ma

Because of the high percentage of fatalities and severe injuries in wrong-way driving (WWD) crashes, numerous studies have focused on identifying contributing factors to the occurrence of WWD crashes. However, a limited number of research effort has investigated the factors associated with driver injury-severity in WWD crashes. This study intends to bridge the gap using a random parameter logit model with heterogeneity in means and variances approach that can account for the unobserved heterogeneity in the data set. Police-reported crash data collected from 2014 to 2017 in North Carolina are used. Four injury-severity levels are defined: fatal injury, severe injury, possible injury, and no injury. Explanatory variables, including driver characteristics, roadway characteristics, environmental characteristics, and crash characteristics, are used. Estimation results demonstrate that factors, including the involvement of alcohol, rural area, principal arterial, high speed limit (>60 mph), dark-lighted conditions, run-off-road collision, and head-on collision, significantly increase the severity levels in WWD crashes. Several policy implications are designed and recommended based on findings.


Author(s):  
Federica Alfani ◽  
Aslihan Arslan ◽  
Nancy McCarthy ◽  
Romina Cavatassi ◽  
Nicholas Sitko

Abstract This paper aims at identifying whether and how sustainable land management practices and livelihood diversification strategies have contributed to moderating the impacts of the El Niño-related drought in Zambia. This is done using a specifically designed survey called the El Niño Impact Assessment Survey, which is combined with the Rural Agricultural Livelihoods Surveys, as well as high resolution rainfall data at the ward level over 34 years. This unique panel data set allows us to control for the time-invariant unobserved heterogeneity to understand the impacts of shocks like El Niño, which are expected to become more frequent and severe as a result of climate change. We find that maize yields were substantially reduced and that household incomes were only partially protected from the shock thanks to diversification strategies. Mechanical erosion control measures and livestock diversification emerge as the only strategies that provided yield and income benefits under weather shock.


2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 40-41
Author(s):  
Hankyung Jun

Abstract Self-employed workers are often reported to have better health than salaried workers. Whether this is because self-employment has health benefits or healthier workers are self-employed is not clear. Self-employed workers may have higher job satisfaction due to higher levels of self-efficacy and autonomy, but may also experience higher job stress, uncertainty, and lack of health insurance leading to mental health problems. Self-employed workers in the U.S. may have different characteristics than those in Mexico and Korea given different working and living environments as well as different institutional arrangements. This study will examine the association between self-employment and mental and cognitive health for older adults in the U.S., Mexico, and South Korea. It uses harmonized panel data from the Health and Retirement Study, the Korean Longitudinal Study of Aging, and the Mexican Health and Aging Study. We compare the health and selection effect of self-employment using a pooled logistic model, fixed-effects model, and a bivariate probit model. In addition to comparing self-employed and salaried workers, we analyze differences between self-employed with and without employees. By using rich data and various models, we address reverse causality and estimate the relationship between self-employment and health. We show that the positive health effects of self-employed workers in the U.S. disappear once controlled for unobserved heterogeneity, indicating the possibility of healthier workers selecting into self-employment. Interestingly, for Korea and Mexico, healthier individuals seem to select into wage work which reflects the difference in working conditions across countries. Further analysis will show effects by business size.


Sign in / Sign up

Export Citation Format

Share Document