Purchasing Power Parity in Some African Countries Using a Nonlinear Panel Unit Root Test
Bibliographic record
Abstract
This study investigates further whether the PPP holds between the US and some 22 African countries from 1st January 1980 to 31st December 2018. The results show that we cannot reject the null hypothesis of a unit root in the 14 series of KSS (2003) demeaned, 10 series of Kruse (2011) demeaned, and 20 series of ADF constant, thus series are non-stationary. Similarly, when de-trended of KSS (2003), detrended of Kruse (2011) and constant and trend of ADF tests were run, both linear and nonlinear unit root tests fail to reject null hypothesis almost all the series under study. The results seem to suggest that real exchange rates are non-stationary in these 22 African countries. The Johansen’s test result shows that deviations from PPP for 12 of 22 countries are persistent.
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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 | 0.001 | 0.007 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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 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".