What a vintage difference measures
Published in Self-published research note, 2026
Recommended citation: Hofer, C. (2026). What a vintage difference measures: hand verification of ownership changes in a public asset-level database. Self-published research note. https://github.com/ochofer/paper1-hazard-exposure-data/releases/download/note-v1.0/what-a-vintage-difference-measures.pdf
Sole-authored measurement note from the data layer behind the climate-risk project. The ownership records that layer depends on are not stable between releases of the source database, and the note asks what a difference between two releases actually records.
The method is hand verification against primary sources: 19 apparent ownership changes drawn at random from the 2,543 that two releases disagree on, each checked against exchange filings, company statements and press releases. The note reports what share turn out to be restatement rather than new coverage, how late the real changes were recorded, and what two undocumented conventions cost a ranking built on the data.
Read the note (PDF). Released with its code and its provenance records.