Robust High-Dimensional Modeling with the Contaminated Gaussian Distribution
Bibliographic record
Abstract
The contaminated Gaussian distribution represents a simple robust elliptical generalization of the Gaussian distribution; differently from the often-considered $t$-distribution, it also allows for automatic detection of outliers, spurious points, or noise (collectively referred to as bad points herein). Starting from this distribution, we propose the contaminated Gaussian factor analysis model as a method for robust data reduction and detection of bad points in high-dimensions. A mixture of contaminated Gaussian factor analyzers model follows therefrom, and extends the recently proposed mixtures of contaminated Gaussian distributions to high-dimensional data, i.e., where $p$ (number of dimensions) is large relative to $n$ (sample size). The number of free parameters is controlled through the dimension of the latent factor space. For each discussed model, we outline a variant of the classical expectation-maximization algorithm for parameter estimation. Various implementation issues are discussed, and we use real data for illustration.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.005 | 0.017 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.003 | 0.003 |
| Open science | 0.003 | 0.003 |
| Research integrity | 0.002 | 0.003 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".