Missing data analysis with sufficient dimension reduction
Bibliographic record
Abstract
Abstract This article develops a two‐step procedure for estimating the unknown parameters in a model that contains a fixed but large number of covariates, more moment conditions than unknown parameters, and responses that are missing at random. We propose a sufficient dimension reduction method to be implemented in the first step and prove that the method is asymptotically valid. In the second step, we apply three well‐known missing data handling mechanisms together with the generalized method of moments to the reduced‐dimensional subspace to obtain estimates of unknown parameters. We investigate the theoretical properties of the proposed methods, including the effects of dimension reduction on the asymptotic distributions of the estimators. Our results refute a claim in an earlier study that dimension reduction yields the same asymptotic distributions of estimators as when the reduced‐dimensional structure is the true structure. We illustrate our method by way of a simulation study and a real clinical trial data example.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".