. Author manuscript; available in PMC: 2016 Jan 20.

Published in final edited form as: Comput Stat Data Anal. 2013 Nov;67:199–212. doi: 10.1016/j.csda.2013.05.011

Table 1. Log quadratic model: results of parameter estimates using the true model, proposed model and Cox PH model.

	α₁				α₂				angle (β̂,β₀)

	bias	SD	SEE	CP	bias	SD	SEE	CP	mean	SD
N = 1000, censoring rate = 80%, 200 cases

true model	0.047	0.153	0.143	0.950	-0.091	0.271	0.251	0.944	6.074	3.517
plSI	0.077	0.163	0.153	0.940	-0.154	0.296	0.272	0.944	7.300	5.430
Cox PH	-0.216	0.114	0.112	0.490	0.425	0.188	0.187	0.374	65.206	35.733

N = 2000, censoring rate = 80%, 400 cases

true model	0.015	0.097	0.097	0.950	-0.034	0.172	0.170	0.952	3.934	2.154
plSI	0.025	0.100	0.101	0.952	-0.055	0.179	0.179	0.950	4.350	2.426
Cox PH	-0.232	0.076	0.077	0.160	0.460	0.122	0.128	0.078	66.075	35.201

N = 1000, censoring rate = 90%, 100 cases

true model	0.082	0.237	0.211	0.936	-0.181	0.432	0.374	0.924	9.417	6.723
plSI	0.153	0.282	0.243	0.952	-0.327	0.502	0.438	0.928	18.288	22.626
Cox PH	-0.196	0.161	0.165	0.722	0.369	0.285	0.279	0.654	64.235	34.882

N = 2000, censoring rate = 90%, 200 cases

true model	0.038	0.154	0.141	0.948	-0.075	0.267	0.246	0.958	6.203	3.750
plSI	0.074	0.163	0.153	0.944	-0.146	0.274	0.271	0.946	7.653	7.039
Cox PH	-0.217	0.111	0.112	0.496	0.435	0.180	0.186	0.354	64.183	34.367

bias: empirical bias; SD: sample standard deviation; SEE: standard error estimate; CP: empirical coverage probability of 95% confidence interval; N: cohort size; plSI: partially linear single index model.