• Journal of the Korean Data and Information Science Society
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• v.28 no.5
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• pp.1077-1085
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• 2017

In this study, we have found the major factors which affect Korean women's wage analysing the data provided by 2015 Korea Labor Panel Survey (KLIPS). In general, wage data is difficult to analyze because random sampling is infeasible. Heckman sample selection model is the most widely used method for analysing the data with sample selection. Heckman proposed two kinds of selection models: the one is the model with maximum likelihood method and the other is the Heckman two stage model. Heckman two stage model is known to be robust to the normal assumption of bivariate error terms. Recently, Marchenko and Genton (2012) proposed the Heckman selectiont model which generalizes the Heckman two stage model and concluded that Heckman selection-t model is more robust to the error assumptions. Employing the two models, we carried out the analysis of the data and we compared those results.

• Informatization Policy
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• v.21 no.2
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• pp.67-88
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• 2014

The research hypothesis of this paper is that education for smart device utilization has a positive effect on ability and utilization of smart devices for the disabled. The data for disabled of NIA's 2012 survey about digital divide is used, and the research method is "Heckman's 2-stage method" which considers the problem of selection bias. As a research result, this paper says that the disabled who had experience of education for smart device utilization have higher level of ability and utilization of smart devices. Also, a high level of education and family income, professional career and young generation have been very positive effect on the high level of ability and utilization of the disabled. The level of ability and utilization of the blind tend to be lower than those of the physically disabled. These results remind that the education for smart device utilization for the disabled is important and effective. And various contents and methods of education which are appropriate for the disability types should be developed.

• Korean Journal of Social Welfare Studies
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• v.43 no.2
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• pp.345-366
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• 2012

This study analyze Family gaps(the wage gap between mothers and non-mothers) across the wages distribution in Korea using 2008 Korean Labor and Income Panel Study. Analysis models include Heckman's two stage estimation to control women's labor participation selection and Quantile regression method to examine the effects of children at different points of the wage distribution. The result indicates that first, comparing non-mothers, mothers with one child suffer statistically significant hourly wage losses at 25th, 50th, and 75th distribution, however not significant effects are found at lowest(10th) and highest(90th) distribution. Second, comparing non-mothers, mothers with two more children suffer statistically significant hourly wage losses at all distribution. Family gap differs across the wage distribution and highest family gaps are found at 25th distribution. With these results, the author suggests universal family policies to support mothers' labor participation and the reconciliation of work and family.

• International Journal of Human Ecology
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• v.4 no.2
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• pp.77-87
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• 2003

This paper tried to construct statistical and econometric models on the basis of economic theory in order to discuss the issue of statistical efficiency and unbiasedness including the sample selection bias correcting problem. Comparative analytical tool were one stage Tobit of Maximum Likelihood estimation and Heckman's two-step Tobit of Ordinary Least Squares. The results showed that the adequacy of model for the analysis on demand and choice, we believe that there is no big difference in explanatory variables between the first selection model and the second linear probability model. Since the Lambda, the self- selectivity correction factor, in the Type II Tobit is not statistically significant, there is no self-selectivity in the Type II Tobit model, indicating that Type I Tobit model would give us better explanation in the demand for and choice which is less complicated statistical method rather than type II model.

• Journal of Korea Trade
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• v.26 no.5
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• pp.1-22
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• 2022

Purpose - This study aims to analyze the influence of South Korea's outward foreign direct investment (OFDI) under the effect of both multinational enterprises' (MNEs) investment motivation and host country institutions. Some suggestions are put forward with regard to South Korean MNEs participating in and integrating into the fierce and changeable world of international market competition. Design/methodology - The basic hypotheses are that MNEs' investment motivations and the host country's superior institutions both boost South Korea's OFDI in those host countries. South Korea's OFDI is divided into investment choice stage and investment scale stage. A Heckman two-stage selection model is established for empirical analysis, using the panel data of South Korea's OFDI and related variables, from 2002 to 2019. Findings - (1) The influence on the investment scale of South Korea's OFDI is more regular and noteworthy than the influence on investment choice. (2) In the investment scale stage, there are obvious motivations to seek markets, labor force and superior technology, but not natural resources. (3) In the investment scale stage, the South Korea's OFDI is more obviously attracted by the host country's superior political institutions, economic institutions and legal institutions, but not cultural institutions. Originality/value - The choices of variables and uses of model expand the theoretical basis and empirical method of OFDI research. The results of the empirical study also provide some reference for the transnational investment of South Korean MNEs and the investment policy formulation of the South Korean government.

• Journal of Labour Economics
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• v.33 no.2
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• pp.135-164
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• 2010

This paper compares the earnings effect of inter-industry technology differences between the self-employed and wage earners. It is assumed that primary skills utilized by the self-employed and paid workers differ in nature, and thus the earnings effect of technology differences and its skill-biasness also differ for each type of workers. For the empirical analysis. Heckman's two-stage method and quantile regressions are fitted to Korean panel data. The earnings effect of technology differences turns skill- biased for wage earners (job-specific skills), but prevails for all self-employed workers (entrepreneurial skills) regardless of their schooling level. This sectoral difference holds for each different quantile of earnings distribution.