Table 1.

Simulation estimated bias, relative bias, and standard error of bias (based on 500 replicates mimicking the dental data, n=200) for mediation (natural direct (D) and indirect (I)) effects on ratio scale; subscripts (20 and 40) indicate times for indirect effects; m indicates the number of (equally spaced) measurements for simulated data. Note: all 500 replicates were used for m = 6 and 11; one resulted in non-convergence (499 were used) for m = 3

		Bias			Rel Bias			SE Bias
Estimand	True╲	m = 3	6	11	m = 3	6	11	m = 3	6	11
Dr	1.350	0.068	0.036	0.022	0.051	0.026	0.017	0.021	0.015	0.012
$I_{20}^r$	1.653	−0.033	0.003	−0.018	−0.018	0.003	−0.009	0.013	0.012	0.011
$I_{40}^r$	1.279	0.060	0.053	0.038	0.048	0.042	0.031	0.009	0.008	0.007
ABCr	13.403	−0.480	−0.821	−0.578	−0.030	−0.057	−0.037	0.237	0.189	0.175
$I_{20}^r$(prop)	0.625	0.107	0.028	0.027	0.174	0.047	0.045	0.056	0.034	0.010
$I_{40}^r$(prop)	0.449	0.220	0.140	0.065	0.445	0.315	0.157	0.321	0.051	0.026
ABCr (prop)	0.598	−0.368	0.060	0.032	−0.650	0.102	0.055	0.483	0.021	0.011