Table 5.
Instrument strength | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Weak | Mod | Strong | |||||||||||
Level | Method | rB | sd | rMSE | pval | rB | sd | rMSE | pval | rB | sd | rMSE | pval |
High | Tr | 1.62 | 0.23 | 0.24 | 0.06 | 0.52 | 0.26 | 0.24 | 0.04 | 1.93 | 0.40 | 0.32 | 0.06 |
Conv | 46.14 | 0.23 | 1.40 | 1.00 | 42.40 | 0.26 | 1.29 | 1.00 | 39.62 | 0.39 | 1.23 | 1.00 | |
2SRI | 14.98 | 0.66 | 0.85 | 0.13 | 9.41 | 0.47 | 0.53 | 0.09 | 8.49 | 0.44 | 0.53 | 0.10 | |
GMM | 72.01 | 315.65 | 5.06 | 0.27 | 75.50 | 109.91 | 4.70 | 0.32 | 71.32 | 60.00 | 4.25 | 0.40 | |
Med | Tr | 0.58 | 0.25 | 0.23 | 0.05 | 1.25 | 0.31 | 0.30 | 0.07 | 1.61 | 0.48 | 0.32 | 0.04 |
Conv | 25.40 | 0.25 | 0.80 | 0.96 | 23.98 | 0.31 | 0.78 | 0.85 | 21.37 | 0.48 | 0.72 | 0.63 | |
2SRI | 9.93 | 0.66 | 0.70 | 0.07 | 6.90 | 0.54 | 0.61 | 0.08 | 5.45 | 0.54 | 0.54 | 0.09 | |
GMM | 36.76 | 47.90 | 43.89 | 0.40 | 32.85 | 32.04 | 2.17 | 0.51 | 44.82 | 41.87 | 3.36 | 0.35 | |
Low | Tr | 0.66 | 0.26 | 0.26 | 0.07 | 1.51 | 0.33 | 0.28 | 0.04 | 2.20 | 0.55 | 0.35 | 0.05 |
Conv | 7.86 | 0.26 | 0.35 | 0.15 | 7.96 | 0.33 | 0.37 | 0.11 | 7.72 | 0.55 | 0.41 | 0.10 | |
2SRI | 6.43 | 0.71 | 0.74 | 0.07 | 5.76 | 0.64 | 0.62 | 0.06 | 5.91 | 0.66 | 0.67 | 0.10 | |
GMM | 22.04 | 31.69 | 2.42 | 0.49 | 26.15 | 31.68 | 3.49 | 0.64 | 43.12 | 25.42 | 4.14 | 0.46 |
Legend: Tr = True model, Conv = Conventional model, 2SRI = Two-Stage Residual Inclusion, GMM = Generalized Method of Moment. Low, Med (Medium), High denote the level of confounding whereas Weak, Mod (Moderate), Strong stand for instrument strength. For the criteria, rB= relative bias (%),sd= standard deviation, rMSE= root Mean Squares error and pval= non-coverage probabilities