Table 2.
Method | Bias | Imprecision | n methoda | ||||
---|---|---|---|---|---|---|---|
Random | Demog | Subscale | Random | Demog | Subscale | ||
25 % missing item rate, psub = 0.5 pitem = 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, psub = 0.5 pitem = 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, psub = 0.2 pitem = 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, psub = 0.1 pitem = 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