| Sample sizes | Normal Exogenous Variables | Uniform Exogenous Variables | ||
| Exact | Over | Exact | Over | |
| 10 | OLS | OLS | OLS | 2SLS |
| 20 | OLS | 2SLS | OLS | 2SLS |
| 30 | OLS | 2SLS | OLS | 2SLS |
| 50 | OLS | 2SLS\3SLS | OLS | 2SLS |
| 100 | 2SLS | FIML | OLS | 2SLS |
| 250 | 2SLS | FIML | OLS | 2SLS |
| 500 | 2SLS | FIML | 2SLS\OLS | FIML\2SLS\3SLS |