Missing value imputation with adversarial random forests - MissARF
Organizations: Leibniz Institute for Prevention Research & Epidemiology – BIPS, Germany · Faculty of Mathematics and Computer Science, University of Bremen, Germany · Department of Informatics, King’s College London, United Kingdom · Department of Public Health, University of Copenhagen, Denmark
Abstract
Handling missing values is a common challenge in biostatistical analyses, typically addressed by imputation methods. We propose a novel, fast, and easy-to-use imputation method called missing value imputation with adversarial random forests (MissARF), based on generative machine learning, that provides both single and multiple imputation. MissARF employs adversarial random forest (ARF) for density estimation and data synthesis. To impute a missing value of an observation, we condition on the non-missing values and sample from the estimated conditional distribution generated by ARF. Our experiments demonstrate that MissARF performs comparably to state-of-the-art single and multiple imputation methods in terms of imputation quality and fast runtime with no additional costs for multiple imputation.
Figures & tables
| Single imputation | Multiple imputation | ||||||
| Method | Data NRMSE | Brier score | Runtime (s) | Coverage rate % | CI width | Coef. RMSE | Runtime (s) |
| [mean (SD)] | [mean (SD)] | [mean] | [median (IQR)] | [median (IQR)] | [median (IQR)] | [mean] | |
| Random Imp. | 1.47 (0.11) | 0.20 (0.05) | <0.1 | 92.0 (46.8) | 0.30 (0.47) | 0.13 (0.11) | <0.1 |
| Median Imp. | 1.21 (0.29) | 0.19 (0.06) | <0.1 | - | - | - | - |
| MissForest | 0.98 (0.19) | 0.18 (0.06) | 16.1 | 90.9 (13.1) | 0.32 (0.47) | 0.12 (0.14) | 322.7 |
| MissForest PMM | 1.26 (0.14) | 0.19 (0.06) | 16.5 | 95.3 (6.0) | 0.32 (0.48) | 0.10 (0.11) | 325.2 |
Appendix figures & tables112 assets
Supplementary material from the paper’s appendix.
Appendix
| Method | ||||||
|---|---|---|---|---|---|---|
| Single | Multiple | Single | Multiple | Single | Multiple | |
| Random Imp. | 0.01 | 0.02 | 0.01 | 0.02 | 0.01 | 0.07 |
| Median Imp. | 0.01 | - | 0.01 | - | 0.01 | - |
| MissForest | 0.92 | 19.59 | 2.17 | 41.59 | 45.11 | 906.93 |
| MissForest PMM | 0.98 | 19.53 | 2.20 | 42.13 | 46.41 | 913.82 |
| MICE PMM | 0.09 | 1.50 | 0.11 | 1.86 | 0.48 | 8.46 |
| Method | ||||||
|---|---|---|---|---|---|---|
| Single | Multiple | Single | Multiple | Single | Multiple | |
| Random Imp. | 0.01 | 0.01 | 0.01 | 0.02 | 0.01 | 0.06 |
| Median Imp. | 0.01 | - | 0.01 | - | 0.01 | - |
| MissForest | 0.27 | 5.59 | 0.40 | 7.70 | 4.86 | 98.33 |
| MissForest PMM | 0.28 | 5.58 | 0.41 | 7.81 | 5.01 | 99.43 |
| MICE PMM | 0.09 | 1.57 | 0.12 | 1.95 | 0.50 | 8.98 |
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