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. 2020 Aug 27;10(8):e033646. doi: 10.1136/bmjopen-2019-033646

Table 1.

Simulation estimates of performance characteristics including mean and Monte Carlo Standard Error in parantheses of different models using each DGP.

Model DGP 1: β3 = 0 DGP 2: β3 = −3 DGP 3: β3 = −3 DGP 4: β3 = −3
Estimate
 MLM 1.1 (0.0024) −1.36  (0.0023) −0.26 (0.0024) −0.23  (0.0025)
 ML Tobit −0.0056 (0.0038) −3.03  (0.0037) −3.04 (0.0037) −3.01  (0.0037)
 ML Tobit σϵ2 = 5 −0.13 (0.0044) −3.01  (0.0042) −3.13 (0.0046) −2.57  (0.0038)
 ML Tobit σϵ2 = 10 −0.093 (0.0044) −3.09  (0.0042) −3.14 (0.0045) −3.05  (0.0041)
 ML Tobit σϵ2 = 15 −0.057 (0.0044) −3.09  (0.0042) −3.12 (0.0045) −3.11  (0.0043)
 ML Tobit σϵ2 = 20 −0.04 (0.0044) −3.08  (0.0042) −3.11 (0.0045) −3.12  (0.0044)
 ML Tobit σϵ2 = 25 −0.031 (0.0044) −3.07  (0.0042) −3.1 (0.0045) −3.11  (0.0044)
 ML Tobit σϵ2 = 30 −0.026 (0.0044) −3.07  (0.0042) −3.09 (0.0045) −3.1  (0.0045)
 OLS SACS 1.1 (0.0024) −1.36  (0.0023) −0.26 (0.0024) −0.23  (0.0025)
 OLS ANCOVA −0.31 (0.0022) −1.36  (0.002) −1.69 (0.0021) −2.43  (0.0019)
 OLS Post −1.36 (0.0023) −1.36  (0.0022) −2.72 (0.0023) −2.69  (0.0018)
 Tobit SACS −0.72 (0.0044) −3.04  (0.0041) −3.78 (0.0044) −4.83  (0.0048)
 Tobit ANCOVA −0.5 (0.0046) −3.09  (0.0042) −3.61 (0.0045) −5.5  (0.0042)
 Tobit Post −3.07 (0.0049) −3.06  (0.0047) −6.13 (0.005) −6.14  (0.004)
Coverage
 MLM 0 (0) 0  (0) 0 (0) 0  (0)
 ML Tobit 94.8 (0.7) 95.3  (0.67) 93.9 (0.76) 95.4  (0.66)
 ML Tobit σϵ2 = 5 67.5 (1.48) 86.7  (1.07) 71.6 (1.43) 4.6  (0.66)
 ML Tobit σϵ2 = 10 83.5 (1.17) 85  (1.13) 77.4 (1.32) 92.2  (0.85)
 ML Tobit σϵ2 = 15 91.1 (0.9) 87.7  (1.04) 85.7 (1.11) 86.8  (1.07)
 ML Tobit σϵ2 = 20 92.7 (0.82) 90  (0.95) 88.2 (1.02) 87.1  (1.06)
 ML Tobit σϵ2 = 25 93.4 (0.79) 91.6  (0.88) 89.5 (0.97) 88.2  (1.02)
 ML Tobit σϵ2 = 30 93.6 (0.77) 91.9  (0.86) 91.1 (0.9) 88.9  (0.99)
 OLS SACS 0 (0) 0  (0) 0 (0) 0  (0)
 OLS ANCOVA 0.8 (0.28) 0  (0) 0 (0) 0  (0)
 OLS post 0 (0) 0  (0) 2.4 (0.48) 0  (0)
 Tobit SACS 0.1 (0.1) 94.4  (0.73) 0 (0) 0  (0)
 Tobit ANCOVA 7.2 (0.82) 89.7  (0.96) 1.2 (0.34) 0  (0)
 Tobit post 0 (0) 93.3  (0.79) 0 (0) 0  (0)
Model SE
 MLM 0.074 (2E-05) 0.074  (2E-05) 0.077 (2E-05) 0.078  (2E-05)
 ML Tobit 0.12 (3E-05) 0.12  (3E-05) 0.12 (3E-05) 0.12  (3E-05)
 ML Tobit σϵ2 = 5 0.1 (3E-05) 0.1  (3E-05) 0.11 (3E-05) 0.11  (4E-05)
 ML Tobit σϵ2 = 10 0.12 (3E-05) 0.12  (3E-05) 0.13 (4E-05) 0.12  (3E-05)
 ML Tobit σϵ2 = 15 0.13 (4E-05) 0.13  (4E-05) 0.14 (4E-05) 0.13  (3E-05)
 ML Tobit σϵ2 = 20 0.13 (5E-05) 0.13  (5E-05) 0.14 (5E-05) 0.14  (4E-05)
 ML Tobit σϵ2 = 25 0.14 (5E-05) 0.13  (5E-05) 0.14 (6E-05) 0.14  (5E-05)
 ML Tobit σϵ2 = 30 0.14 (5E-05) 0.13  (5E-05) 0.15 (6E-05) 0.14  (5E-05)
 OLS SACS 0.074 (2E-05) 0.074  (2E-05) 0.077 (2E-05) 0.078  (2E-05)
 OLS ANCOVA 0.07 (2E-05) 0.065  (2E-05) 0.072 (2E-05) 0.059  (2E-05)
 OLS post 0.07 (2E-05) 0.07  (2E-05) 0.072 (2E-05) 0.055  (2E-05)
 Tobit SACS 0.13 (5E-05) 0.13  (5E-05) 0.14 (6E-05) 0.15  (6E-05)
 Tobit ANCOVA 0.14 (6E-05) 0.14  (6E-05) 0.15 (6E-05) 0.13  (6E-05)
 Tobit post 0.15 (7E-05) 0.15  (6E-05) 0.16 (7E-05) 0.13  (6E-05)

ANCOVA, analysis of covariance; DGP, data generating process; MLM, multilevel model; OLS, ordinarily least squares; SACS, Simple Analysis of Change Scores.