Table 3 Estimates of OLS-Pool and Two-Step Difference GMM models
From: Physician induced demand for knee replacement surgery in Iran
Independent Variables | OLS-Pool | Two-Step Difference GMM | ||||
|---|---|---|---|---|---|---|
\(\dot{{\mathbf{y}}_{\mathbf{it}}}=\dot{{\mathbf{n}}_{\mathbf{it}}}\) (1) | \(\dot{{\mathbf{y}}_{\mathbf{it}}}=\dot{{\mathbf{s}}_{\mathbf{it}}}\) (2) | \(\dot{{\mathbf{y}}_{\mathbf{it}}}=\dot{{\mathbf{f}}_{\mathbf{it}}}\) (3) | \(\dot{{\mathbf{y}}_{\mathbf{it}}}=\dot{{\mathbf{n}}_{\mathbf{it}}}\) (4) | \(\dot{{\mathbf{y}}_{\mathbf{it}}}=\dot{{\mathbf{s}}_{\mathbf{it}}}\) (5) | \(\dot{{\mathbf{y}}_{\mathbf{it}}}=\dot{{\mathbf{f}}_{\mathbf{it}}}\) (6) | |
\(\dot{{\mathrm{d}}_{\mathrm{it}}}\))SE( | 0.71a (0.03) | 0.79a (0.03) | 0.07 (0.01) | 0.94a (0.05) | 1.01aa (0.04) | 0.06a (0.02) |
\(\dot{{\mathrm{y}}_{\mathrm{it}-1}}\) )SE( | 0.63a (0.02) | 0.63a (0.02) | 0.68a (0.03) | -0.04a (0.05) | 0.07a (0.03) | 0.11a (0.05) |
\(\dot{\mathrm{inc}\ }\))SE( | 0.15 (0.08) | 0.09a (0.07) | -0.04 (0.02) | -1.25 (1.88) | 0.80 (0.33) | 0.54 (0.35) |
Constant | 7.96a (1.51) | 13.06a (1.69) | 4.35a (0.85) | 36.18a (32.56) | 11.85a (10.96) | 0.84a (5.94) |
N. observation | 823 | 823 | 823 | 823 | 823 | 823 |
R-squared | 0.826 | 0.805 | 0.473 | |||
F-test (p-value) | 0.000 | 0.000 | 0.036 | |||
Wald test | 601.34 | 599.96 | 8.55 | |||
Hansen test | 0.361 | 0.284 | 0.413 | |||
Sargan test | 0.277 | 0.175 | 0.339 | |||
M2 test | 0.671 | 0.589 | 0.712 | |||