Handling missing items in the Hospital Anxiety and Depression Scale (HADS): a simulation study

Bell, Melanie L.; Fairclough, Diane L.; Fiero, Mallorie H.; Butow, Phyllis N.

doi:10.1186/s13104-016-2284-z

BMC Research Notes

Table 2 Mean bias and imprecision of individual scores for depression, n = 52 for random, demographic and subscale dependent missingness mechanisms

From: Handling missing items in the Hospital Anxiety and Depression Scale (HADS): a simulation study

Method	Bias			Imprecision			n method^a
Method	Random	Demog	Subscale	Random	Demog	Subscale	n method^a
25 % missing item rate, p_sub = 0.5 p_item = 0.5
Subject mean	0.083	0.002	−0.060	1.638	1.707	2.177	52
Subscale mean	0.004	−0.007	−0.010	2.316	2.533	3.483	52
Subscale ½ mean	0.006	−0.002	−0.003	0.617	0.637	0.886	40
Item mean	0.001	−0.360	−1.110	2.755	3.453	4.745	52
Multiple imputation	0.016	−0.087	−0.324	1.727	2.043	2.623	52
Multiple imputation ½	0.010	−0.027	−0.119	0.635	0.738	0.965	40
10 % missing item rate, p_sub = 0.5 p_item = 0.2
Subject mean	0.028	0.002	−0.025	0.459	0.474	0.632	52
Subscale mean	−0.003	0.001	−0.002	0.526	0.543	0.767	52
Subscale ½ mean	−0.002	0.001	−0.000	0.437	0.453	0.631	47
Item mean	−0.002	−0.123	−0.372	0.747	0.897	1.052	52
Multiple imputation	0.005	−0.012	−0.075	0.532	0.612	0.773	52
Multiple imputation ½	0.001	−0.007	−0.063	0.472	0.545	0.672	47
10 % missing item rate, p_sub = 0.2 p_item = 0.5
Subject mean	0.034	−0.003	−0.082	0.674	0.685	0.991	52
Subscale mean	−0.001	−0.004	0.001	0.986	1.025	1.468	52
Subscale ½ mean	0.004	−0.002	−0.001	0.212	0.212	0.313	47
Item mean	−0.002	−0.132	−0.702	1.102	1.310	3.435	52
Multiple imputation	0.005	−0.027	−0.234	0.662	0.751	1.276	52
Multiple imputation ½	0.002	−0.007	−0.074	0.195	0.222	0.363	47
2 % missing item rate, p_sub = 0.1 p_item = 0.2
Subject mean	0.006	−0.000	−0.023	0.091	0.098	0.151	52
Subscale mean	−0.000	−0.000	0.001	0.106	0.110	0.158	52
Subscale ½ mean	0.000	0.000	0.001	0.083	0.086	0.128	51
Item mean	0.000	−0.029	−0.164	0.141	0.177	0.541	52
Multiple imputation	0.001	−0.004	−0.038	0.101	0.112	0.192	52
Multiple imputation ½	0.000	−0.002	−0.033	0.086	0.193	0.163	51

1000 simulated datasets
^aSample size after imputation

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ISSN: 1756-0500

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