This work was supported by Major Program of National Social Science Foundation of China [Project No. 11&ZD151 ], Humanities and Social Sciences Research Funds from the Ministry of Education of China [Project No. 15YJA190001 ], Fundamental Research Funds of Central China Normal University [Project No. CCNU14Z02004 ], and Research Program Funds of the Collaborative Innovation Center of Assessment toward Basic Education Quality at Beijing Normal University [Project No. 2016-04-003-BZK01 ; 2016-04-009-BZK01 ]. The authors have declared that they have no competing or potential conflicts of interest.