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Record W1466377058 · doi:10.1017/cbo9780511611131.009

Likelihood approximations

2007· book-chapter· en· W1466377058 on OpenAlexaff
Alessandra Rosalba Brazzale, A. C. Davison, Nancy Reid

Bibliographic record

VenueCambridge University Press eBooks · 2007
Typebook-chapter
Languageen
FieldComputer Science
TopicAdvanced Mathematical Modeling in Engineering
Canadian institutionsUniversity of Toronto
Fundersnot available
KeywordsApproximations of πOrder (exchange)MathematicsApplied mathematicsCalculus (dental)Mathematical economicsComputer scienceEconomicsMedicine

Abstract

fetched live from OpenAlex

Introduction In this chapter we give a brief overview of the main theoretical results and approximations used in this book. These approximations are derived from the theory of higher order likelihood asymptotics. We present these fairly concisely, with few details on the derivations. There is a very large literature on theoretical aspects of higher order asymptotics, and the bibliographic notes give guidelines to the references we have found most helpful. The building blocks for the likelihood approximations are some basic approximation techniques: Edgeworth and saddlepoint approximations to the density and distribution of the sample mean, Laplace approximation to integrals, and some approximations related to the chi-squared distribution. These techniques are summarized in Appendix A, and the reader wishing to have a feeling for the mathematics of the approximations in this chapter may find it helpful to read that first. We provide background and notation for likelihood, exponential family models and transformation models in Section 8.2 and describe the limiting distributions of the main likelihood statistics in Section 8.3. Approximations to densities, including the very important p * approximation, are described in Section 8.4. Tail area approximations for inference about a scalar parameter are developed in Sections 8.5 and 8.6. These tail area approximations are illustrated in most of the examples in the earlier chapters. Approximations for Bayesian posterior distribution and density functions are described in Section 8.7. Inference for vector parameters, using adjustments to the likelihood ratio statistic, is described in Section 8.8.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.004
metaresearch head score (Gemma)0.048
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Theoretical or conceptual · Consensus signal: Theoretical or conceptual
GenreCandidate signal: Methods · Consensus signal: Methods
Teacher disagreement score0.030
Threshold uncertainty score0.100

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0040.048
Meta-epidemiology (narrow)0.0010.001
Meta-epidemiology (broad)0.0020.002
Bibliometrics0.0020.003
Science and technology studies0.0010.002
Scholarly communication0.0040.006
Open science0.0030.003
Research integrity0.0020.005
Insufficient payload (model declined to judge)0.0300.015

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.

Opus teacher head0.031
GPT teacher head0.217
Teacher spread0.186 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designTheoretical or conceptual
Domainnot available
GenreMethods

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".

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Citations0
Published2007
Admission routes1
Has abstractyes

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