xtabond2 pe l.pe lncomp, gmm(lncomp, collapse) iv(d.lncomp) robust twostep
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Dynamic panel-data estimation, two-step system GMM

Group variable: code                            Number of obs      =     12858
Time variable : year                            Number of groups   =      1772
Number of instruments = 14                      Obs per group: min =         1
Wald chi2(2)  =    187.47                                      avg =      7.26
Prob > chi2   =     0.000                                      max =        11

Corrected
pe               Coef.        Std. Err.        z      P>z        [95% Conf. Interval]

pe
L1.            .7166423   .1143033     6.27   0.000     .4926119    .9406727

lncomp     .1104304   .0096764    11.41   0.000      .091465    .1293959
_cons     -1.396362   .1272318   -10.97   0.000    -1.645732   -1.146993

Instruments for first differences equation
Standard
D.(D.lncomp)
GMM-type (missing=0, separate instruments for each period unless collapsed)
L(1/.).lncomp collapsed
Instruments for levels equation
Standard
_cons
D.lncomp
GMM-type (missing=0, separate instruments for each period unless collapsed)
D.lncomp collapsed

Arellano-Bond test for AR(1) in first differences: z =  -3.65  Pr > z =  0.000
Arellano-Bond test for AR(2) in first differences: z =   1.83  Pr > z =  0.067

Sargan test of overid. restrictions: chi2(11)   =  95.28  Prob > chi2 =  0.000
(Not robust, but not weakened by many instruments.)
Hansen test of overid. restrictions: chi2(11)   =  96.19  Prob > chi2 =  0.000
(Robust, but can be weakened by many instruments.)

Difference-in-Hansen tests of exogeneity of instrument subsets:
GMM instruments for levels
Hansen test excluding group:     chi2(10)   =  75.20  Prob > chi2 =  0.000
Difference (null H = exogenous): chi2(1)    =  20.99  Prob > chi2 =  0.000
iv(D.lncomp)
Hansen test excluding group:     chi2(10)   =  63.18  Prob > chi2 =  0.000
Difference (null H = exogenous): chi2(1)    =  33.01  Prob > chi2 =  0.000