Popov artificially induced MCAR, MAR, and MNAR gaps (total missingness 9.72β48.83%) into two public binary-classification datasets (Churn: 10,000 records; Wine: 1,599 records), imputed them with listwise deletion, mean imputation, scikit-learn IterativeImputer, and R MICE, then trained LR, SVC, RF, and LGBM classifiers on an 80/20 splitβyielding 48 Churn and 36 Wine imputed datasets . The headline result: R MICE delivered the most reliable, least fluctuating metrics across all mechanisms, and RF sometimes outperformed its own complete-data baseline when paired with MICEβconsistent with the related finding that no single imputation method universally dominates and test-set missingness strongly shapes outcomes .
Strengths: systematic coverage of all three missingness mechanisms plus mixed designs; imputation restricted to training data preserves a fair common test set; per-mechanism and per-metric (accuracy vs recall) breakdowns are unusually granular for a methods comparison.
Weaknesses the paper partially acknowledges but does not resolve: (1) only two tabular datasetsβgeneralizability claims rest on 84 experimental cells from this narrow base; (2) no statistical testing, confidence intervals, or variance across random seeds, so claims like 'MICE is most reliable' rest on eyeballed rank stability; (3) computational costβthe paper's own cited literature notes simple methods gain 'considerably in computational power' over complex ones, yet runtime is never reported despite the title emphasizing 'efficiency' ; (4) the IterativeImputer finding (poor with RF/LGBM on Churn) is dataset-specific and could reflect default hyperparameters rather than method failure; (5) single train/test split with no repeated cross-validation invites selection noise.
Context: the paper's conclusion that MICE-type multiple imputation is the safest default aligns with an independent COVID-19 study where MICE achieved ~26% accuracy improvement over baseline methods , but a time-series study found mean imputation best (RMSE 1.78 vs 3.45β4.67 for alternatives) βreinforcing Popov's own caveat that imputation performance is data-dependent and no universal winner exists.
What would change the conclusion: multi-seed replication with CIs showing MICE's advantage is within noise, or its inclusion of modern methods (MissForest, GAIN, MIWAE, KNN) that the referenced Shadbahr benchmark found competitive or superior would overturn the 'MICE is best' ranking.
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