Does pattern mixture modelling reduce bias due to informative attrition compared to fitting a mixed effects model to the available cases or data imputed using multiple imputation?: a simulation study

Welch, Catherine A.; Sabia, Séverine; Brunner, Eric; Kivimäki, Mika; Shipley, Martin J.

doi:10.1186/s12874-018-0548-0

Table 2 Correlations among variables in full simulated global cognitive function data and differences compared to correlations among variables in available case analyses data, data imputed using multiple imputation and after applying pattern mixture modelling

From: Does pattern mixture modelling reduce bias due to informative attrition compared to fitting a mixed effects model to the available cases or data imputed using multiple imputation?: a simulation study

		Global cognitive function				Smoking status		Age	Grade	Education
	Phase	5	7	9	5	7	9	5	5	5
Full simulated data	Global 5	1
	Global 7	0.9686	1
	Global 9	0.9629	0.9691	1
	Smoke 5	−0.0721	− 0.0860	− 0.0978	1
	Smoke 7	−0.0595	− 0.0721	− 0.0824	0.9561	1
	Smoke 9	−0.0467	− 0.0587	− 0.0693	0.9233	0.9537	1
	Age	−0.2280	− 0.2780	− 0.3293	0.0356	0.0440	0.0538	1
	Grade	−0.4746	− 0.4462	− 0.4203	0.1134	0.0985	0.0905	−0.0516	1
	Education	0.3794	0.3721	0.3664	−0.1144	− 0.1056	− 0.1053	− 0.0782	− 0.3666	1
Differences^a in correlations from those above
Available case	Global 5	0
	Global 7	0.0055	0
	Global 9	0.0025	0.0067	0
	Smoke 5	−0.0051	0.0035	0.0062	0
	Smoke 7	− 0.0058	0.0011	0.0019	−0.0047	0
	Smoke 9	−0.0106	− 0.0022	− 0.0025	− 0.0051	−0.0011	0
	Age	−0.1419	−0.1809	− 0.2112	−0.0332	− 0.0283	−0.0265	0
	Grade	−0.0142	− 0.0036	− 0.0020	0.0107	0.0099	0.0086	−0.0040	0
	Education	0.0503	0.0535	0.0446	−0.0162	− 0.01520	− 0.0133	− 0.0351	−0.0342	0
Multiple imputation	Global 5	0
	Global 7	0.0028	0
	Global 9	0.0198	0.0070	0
	Smoke 5	0.0463	0.0485	0.0593	0
	Smoke 7	0.0481	0.0505	0.0631	0.0073	0
	Smoke 9	0.0389	0.0436	0.0564	0.0130	0.0076	0
	Age	−0.0160	−0.0205	0.0013	−0.1233	− 0.1276	− 0.1280	0
	Grade	0.0078	0.0141	0.0063	−0.0173	− 0.0173	− 0.0122	0	0
	Education	0.0009	−0.0010	−0.0008	0.0280	0.0260	0.0298	0	0	0
Pattern mixture modelling	Global 5	0
	Global 7	0.0102	0
	Global 9	0.0275	0.0076	0
	Smoke 5	0.0463	0.0568	0.0679	0
	Smoke 7	0.0481	0.0581	0.0710	0.0073	0
	Smoke 9	0.0389	0.0511	0.0637	0.0130	0.0076	0
	Age	−0.0160	− 0.0190	− 0.0021	− 0.1233	− 0.1276	− 0.1280	0
	Grade	0.0078	0.0173	0.0112	−0.0173	− 0.0173	− 0.0122	0	0
	Education	0.0009	−0.0035	−0.0038	0.0280	0.0260	0.0298	0	0	0

^aDifferences in correlations are calculated as correlation in analysis type minus correlation in full simulated data

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ISSN: 1471-2288

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