st: The explanation of Sargan statistic and Endogeneity test

["George_Huang" <cjhuang168@gmail.com>]

Dear all:

I ran the comment ivreg2, and got the following results:


Sargan statistic (overidentification test of all instruments): 
8.553
                                                  Chi-sq(3) P-val = 
0.0359
-endog- option:
Endogeneity test of endogenous regressors: 
1.992
                                                  Chi-sq(2) P-val = 
0.3693
Regressors tested:    lagfam lagins

I have two questions:

1. How can I explain the above results?


2. Does it mean that there is no endogeneity problem and I can use the 
comments of xtreg or reg instead, or I have to make sure the p-value of 
Sargan statistic is not significant  first to make further conclusion? If 
you have any suggestions, please let me know.



Thanks,



George



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