2.3 Data envelopment analysis
In order to get more information about the production efficiency and the efficiency of heterogeneous human capital in different regions，take the variables that explained GDP well，analysis using Data Envelopment Analysis（DEA）method.
DEA method is used to analyze the input and output efficiency of the Decision Making Unit（DMU）with linear programming.DEA method is to construct the production frontier by keeping the output or input of the DMU projection to the production frontier，and to evaluate their relative effectiveness by comparing the degree of DMU away from the DEA production frontier.
To determine whether the DMU is DEA effective，in essence，is to determine whether DMU is located in the production of a possible set of“production frontier”.This requires that the input of the DMU is the lesser the better，and the output of the DMU is the larger the better.The input part of DMU more than“enough”is called“input redundancy”，the output part of DMU less than“enough”is called“output deficiency”.
Take C2 R model as an example.Take n provincial areas as DMUs.The DMUs have the input index of M types and the output index of Ptypes.Set the input vector is Xj＝（x1j，x2j，…，xmj），the output vector is Yj＝（y1j，y2j，…，ypj）.The relative performance of the j0DMU is constructed by the following DEA model：
X0 is the input vector of the j0 DMUs.Y0 is the output vector of the j0 DMUs.Solve the linear programming problem of model 6.Set the optimal value asθ＊，if θ＊＝1，so the decision unit j0 is a relatively effective unit of operation.S-or S＋in the model is a slack variable，can be used to reflect the input redundancy and output deficiency.If S-is more than zero，that is called the input redundancy.If the value of S＋is more than zero，that is called the output insufficient.
∑λj can reflect the changing trend of scale returns of the DMU.If ∑λj more than 1，so scale returns diminish.If ∑λj equal 1，so scale returns unchanged.If ∑λj less than 1，so scale returns increase.
Table 3 DEA results
Continued Table 3
DEA model results show that，relatively effective DMUs are Beijing，Shanghai，Guangdong，Tibet.Scale efficiency in most provinces showed an increasing state except Tianjin，Hebei，Inner Mongolia，Liaoning，Jiangsu，Zhejiang，Fujian，Shandong provinces（city）.Study the input redundancy 
and the output value 
can find out that the main reason of the non DEA effective is the redundancy of the heterogeneous human capital.Most of the provinces have redundant human capital in junior middle school education，only a few provinces have redundant human capital in senior middle school education human capital and college and above education human capital.
Liaoning and Qinghai have redundancy in college degree or above education human capital.Tianjin，Jiangsu，Jiangxi，Hubei，Hainan have redundancy in the senior middle school education human capital.
The regional structure adjustment of the heterogeneous human capital can be referred to the redundant information.Redundant human capital can flow in two directions.One way is the human capital flow to other levels（by means of additional human capital investment）.The other way is the human capital flow to other regions.
The human capital has the characteristic of one direction in the flow of different levels.The lower human capital can change to advanced human capital with the help of human capital investment.But the promotion of human capital can't leapfrog completely，needs to realize step by step，and the way is through all kinds of education at all levels of human capital investment.
In addition to Beijing，Shanghai，Guangdong，Tibet，Tianjin，Jiangsu，Jiangxi，the main task of other provinces is to strengthen the investment of high school education（ordinary senior high school and the corresponding level vocational education），to realize the transformation of human resources to the high level heterogeneous human capital.
The problems of college education（college degree and above）in recent years，especially the employment problems of college graduates，draw people's attention away from middle school education，especially the attention on the secondary vocational education.
The research shows that the senior middle school education（ordinary high school and the corresponding level vocational education）is the effective way to solve the redundancy of the human capital investment in most provinces.23 provinces emerge redundancy in the junior middle school education human capital.In the 23 provinces，only Hainan emerges redundancy in the senior middle school education human capital，other provinces have the space for human capital to flow in from other regions.In addition，from the perspective of human capital regional flow，the feasible way is that the human capital flows from the region with input redundancy in human capital to other regions.
The redundant human capital should flow from the original region.There are special requirements for the inflow regions：Firstly，the region that the human capital wants to flow into can't be redundant in human capital.Secondly，the region that the human capital wants to flow into must be in the stage of increasing returns to scale.Otherwise，continue to increase investment in human capital will lead to the redundancy of human capital investment in the region，and can't improve the efficiency of human capital investment.Moreover，because of the difference between the regional social economy and cultural development，there are not too many places that can meet such conditions for the smooth flow.Therefore，solving the problem of human capital investment mainly depends on changing the level of human capital in this region，but not depending on changing the region of human capital.