Hi! How do I interpret coefficients that have different signs with deeper lags of system GMM? This is the effect of urbanization on health:

Code:
 urban |
         --. |  -.0000123   .0000234    -0.52   0.602    -.0000589    .0000344
         L1. |   .0000486    .000022     2.21   0.030     4.86e-06    .0000924
         L2. |   -.000046   .0000267    -1.73   0.089    -.0000991    7.11e-06
Thanks!