A simple estimation method and finite-sample inference for a stochastic volatility model
Bibliographic record
Abstract
The aim of the paper is to fulfill the gap for testing hypotheses on parameters of the log-normal stochastic volatility model, more precisely, to propose finite sample exact tests in the sense that the tests have correct levels in small samples. To do this, we examine method-of-moments-based tests and we provide explicit expressions for all the moments and the estimators which simplifies highly the test procedures. We then state the asymptotic distribution of the estimator as well as that of the proposed test statistics for testing the null hypothesis of no persistence in the volatility. We then compare in a study of level and power the standard asymptotic techniques to the technique of Monte Carlo tests which is valid in finite samples and allow for test statistics whose null distribution may depend on nuisance parameters. In particular maximized Monte Carlo tests (MMC) introduced by Dufour (1995) have the exact level in finite samples when the p-value function is maximized over the entire set of nuisance parameters. In contrast to MMC tests which are highly computer intensive, simplified (asymptotically justified) approximate versions of Monte Carlo tests provide a halfway solution which achieves to control the level of the tests while alleviating the use of computers.
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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 | 0.007 | 0.047 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 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".