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