Bibliographic record
Abstract
Purpose The purpose of this paper is to revisit the evidence for purchasing power parity (PPP) using long, low‐frequency data (over 100 years) for 23 organization for economic co‐operation and development (OECD) countries against each of four different base currencies – the Deutsch mark, the Japanese yen, the British pound, and the US dollar. Design/methodology/approach The paper uses standard unit root tests and level and trend stationarity tests, and also investigates the robustness of the results to alternative testing methodologies from statistical physics, such as Lo's modified rescaled range statistic and the Hurst exponent. Findings The results indicate that the theory of PPP does not hold. Originality/value Motivated by the mixed results from previous research on the validity of the theory of PPP, the robustness of standard unit root and stationarity tests to alternative testing methodologies are investigated. In particular, the paper uses two tests from statistical physics – Lo's modified R / S statistic and the Hurst exponent.
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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 | 0.003 | 0.022 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.004 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.011 | 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".