Abstract:      The competition among different countries is essentially a competition for talents, therefore at present many countries have taken strong measures to attract and retain talents at the high-end. Accurately evaluating the impact of the "Overseas Youth Talent-Attracting Program" (OYTP) on universities′ research output is of important practical significance for the implementation and improvement of China′s talent policy. Currently, the academic community mainly cares the development from the perspectives of the "OYTP" candidates, such as why they choose to return home from abroad, what feature the group has and how many researches they can output. However, no matter for academic staff or administrative staff, what they should be more concerned about is the output of scientific research after introduction of "OYTP" candidates. As the number of full-time "Overseas Talent-attracting Program" candidates is relatively small, it is more practical to study the full-time "OYTP" candidates. This paper takes "University of 211 Project" as the research object and adopts the method of Differences-in-Differences (DID) to analyze the influence of "OYTP" on universities′ chemical research output.After reviewing and summarizing the current research status at home and abroad, this paper refines some innovation points and proposes the following assumptions based on the theory of S&T human capital and the theory of diminishing marginal effect. H1a: "OYTP" candidates can increase the quantity of universities′ research output; H1b: "OYTP" candidates can improve the quality of universities′ research output. Considering that there are significant differences in factor endowment between universities with different academic levels, which may lead to significant differences in the effect of the same policy, the variable of academic level of universities is introduced, and H2a and H2b are therefore proposed. H2a: Compared with universities with high academic level, "OYTP" candidates play a greater role in promoting the quantity of research output of universities with low academic level. H2b: Compared with universities with high academic level, "OYTP" candidates play a greater role in promoting the quality of research output of universities with low academic level. As a talent policy, the method of DID is adopted by this paper to evaluate the policy effect of "OYTP". As of 2015, 43 universities of 211 Project that have successively introduced "OYTP" candidates in chemistry can be considered as the treatment group, and other universities of 211 Project that have not introduced "OYTP" candidates in chemistry can be considered as the control group, which the quasi-natural experiment can be conducted. Based on the research content, we constructed two analysis models and retrieved the number of papers and cited papers in chemistry in the ESI database of 95 universities from 2008 to 2017. As a result, we found a total of 399,189 papers in chemistry and the total number of paper citations was 6,746,678. Then, the CV analysis was used to extract the basic information of "OYTP" candidates such as the names, ages, introduction units and introduction batches from the list of "OYTP" to form a complete set of personal information. Based on the basic information, this paper measures whether the university introduced "OYTP" candidates in chemistry and when. The empirical analysis then leads to the following conclusions:First, "OYTP" has positively influenced the quantity and quality of universities′ research output, with the quality of output being more substantially improved. The research results show that the quantity and quality of research output of universities with the "OYTP" candidates are 0.80% and 1.11% respectively higher than those of universities without, and "OYTP" candidates play a greater role in improving the quality of universities′ research output. These "OYTP" candidates have been able to provided high-level human capital and social capital to universities, which is conductive to access to research funding as well as infrastructure improvements, and has got significant fruits in boosting research output of universities. Therefore, universities can give full play to the policy effect of the "OYTP", improve the quality of scientific research of universities by introducing "OYTP" candidates, and speed up the construction of becoming "double first-rate" universities.Second, the "OYTP" has a diminishing marginal effect on research output universities, which means the introduction of "OYTP" candidates in universities with low academic level has a greater contribution to research output compared to universities with high academic level. This provides a rapid development opportunity for universities with low academic level. Therefore, universities with low academic level should make full use of their social resources, reach an intention to introduce outstanding overseas talents, and accelerate the discipline construction and improve the level of disciplines by introducing "OYTP" candidates. Universities with relatively high academic levels can introduce "OYTP" candidates on demand, pay attention to the balance of resource allocation between returnee scientists and local scientists, reduce or even avoid the negative effects caused by unfair policy, so as to give full scope to the talents and do their best to avoid the loss of returnee scientists. Third, university research funding act as a partial intermediary between the "OYTP" and universities′ research output. The impact of the "OYTP" on universities′ research output is not transmitted exclusively through access to research funding, since the introduction of "OYTP" candidates can directly contribute to research output, particularly the quality. Therefore, on the one hand, universities should attach importance to the role of "OYTP" candidates in obtaining funding for scientific research, and increase the level of research output by increasing the scale of scientific research funding. On the other hand, universities cannot overemphasize the role of scientific research funding in promoting research output and should give full play to the human capital of "OYTP" candidates, because they can directly promote universities′ research output as a high-level human capital.

Key words: Overseas Youth Talent-Attracting Program (OYTP), difference-in-difference method, universities′ research output, talent policy