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. 2009 Aug 13;4(8):e6624. doi: 10.1371/journal.pone.0006624

Table 3. Analysis of ITT-LOCF, LOCF, and completers for handling missing data in the 12 raw datasets using ordinary least squares.

Actual Analysis Null Imposed Treatment Effect
ITT-LOCF Observed Mean Difference Observed p-value Permuted p-value Empirical α Mean Difference Power
RCT 1a 4.07 1×10−5 <10−5 .0479 1.99 .539
RCT 2 a 2.60 .0103 .0113 .0522 2.13 .528
RCT 3 0.62 .2827 .2837 .0510 1.19 .515
RCT 4 5.01 <10−5 <10−5 .0505 2.26 .489
RCT 5 7.17 .0022 .0005 .0469 5.29 .482
RCT 6 0.03 .9551 .9561 .0510 1.17 .414
RCT 7 1.66 .2344 .2252 .0478 2.55 .429
RCT 8 1.66 .4133 .4270 .0485 3.71 .413
RCT 9 0.71 .3881 .3971 .0517 1.57 .443
RCT10 1.90 <10−5 <10−5 .0474 0.56 .537
RCT 11 a 1.30 .0009 .0006 .0531 0.82 .541
RCT 12 1.05 .0001 .0003 .0496 0.53 .481
LOCF
RCT 1a 4.07 1×10−5 <10−5 .0479 1.99 .539
RCT 2 a 2.60 .0103 .0113 .0522 2.13 .528
RCT 3 0.61 .2964 .2976 .0509 1.21 .515
RCT 4 4.95 <10−5 <10−5 .0497 2.34 .502
RCT 5 9.12 .0005 <10−5 .0459 6.09 .511
RCT 6 0.39 .5906 .5868 .0498 1.50 .498
RCT 7 1.81 .2075 .2015 .0471 2.87 .508
RCT 8 2.09 .3731 .3825 .0471 4.48 .457
RCT 9 0.83 .3702 .3730 .0483 1.87 .500
RCT10 1.93 <10−5 <10−5 .0468 0.57 .537
RCT 11 a 1.30 .0009 .0006 .0531 0.82 .541
RCT 12 1.10 .0002 .0004 .0492 0.57 .484
Completers
RCT 1 4.72 2×10−5 <10−5 .0474 1.90 .390
RCT 2 2.71 .0140 .0133 .0513 2.18 .480
RCT 3 0.65 .3767 .3759 .0523 1.34 .424
RCT 4 5.32 <10−5 <10−5 .0470 2.37 .451
RCT 5 9.34 .0038 .0011 .0484 6.12 .375
RCT 6 0.44 .6058 .6052 .0505 1.66 .468
RCT 7 2.14 .1880 .1842 .0475 2.74 .389
RCT 8 0.56 .8261 .8531 .0379 5.28 .512
RCT 9 1.58 .4435 .4403 .0512 2.27 .176
RCT10 0.88 .3411 .3497 .0500 0.65 .107
RCT 11 1.39 .0029 .0021 .0537 0.92 .490
RCT 12 1.42 .0030 .0038 .0500 0.66 .279

Abbreviations: ITT-LOCF, intent-to-treat-last observation carried forward; RCT, randomized controlled trial.

a

Indicates missing data pattern is the same for ITT-LOCF and LOCF. Each permutation test is based on 10,000 permutations of each dataset.