Islands of Stability, expansions in many countries: pre-registration (r1)

This deposit fixes, before anything is computed, test X1 of proposition 3 of Islands of Stability (islandsofstability.com), the first test written against the proposition's version 0.2 wording: under a stationary disturbance, exit from an island of given depth is memoryless. Do economic expansions grow more or less likely to end as they age, when each country's expansions are compared only with each other and each decade is allowed its own level? Expansions are dated by Harding and Pagan's BBQ rule in the OECD's quarterly real GDP for 42 countries, using measured quarters only, up to 2019 Q4; the pandemic is reported alongside. Published work on industrial countries (Castro, 2010) is disclosed in the document. Nothing in this deposit has been computed. Before the freeze only the data file's structure was read: column names, country codes, and each country's dates and status flags. The test uses no random numbers; run_test.py requires this record's DOI so that the statistics can only be computed after the dated deposit, and refuses to run unless every frozen file matches lock.json and the data file matches its recorded SHA-256. Contents of bundle.zip (SHA256SUMS lists a hash for every file): PREREGISTRATION.md: the frozen document (r1), also uploaded on its own; PREREGISTRATION-draft.md is the draft (r0), kept for the record. lock.json and freeze.py: the SHA-256 of every frozen file, and the check (python freeze.py --verify). bbq.py, hazard.py, qna.py, run_test.py: the dating rule, the hazard model, the data reader and the runner (python run_test.py --doi ). data/qna_gdp_volume.csv: the data, unchanged, from the OECD's Quarterly National Accounts, under CC BY 4.0 (credit: OECD); data/SOURCE.md gives its query, retrieval time and SHA-256. tests/: unit tests on made-up data (python -m pytest -q tests). The code and documents are under the Apache License 2.0; the data file stays under the OECD's CC BY 4.0. Related: the pre-registration of the site's first instrument, snapshot 1 of the Map (10.5281/zenodo.22982434). Drafted with Claude (Anthropic), an AI assistant; every decision recorded in the document was made by the author.