Progressivity of the personal income tax schedule, including top marginal rates, bracket spread, and targeted credits (EITC-equivalents).
General government spending as share of GDP, excluding transfers already captured under fiscal.transfer_expansion to avoid double-counting.
Solidaritätszuschlaggesetz 24 June 1991 introduced a 7.5% surcharge on income and corporate tax 1991-1992 to finance reunification and Gulf War costs. Reintroduced at 7.5% in 1995, reduced to 5.5% from 1998. Partially abolished from 2021 for lower-income taxpayers. Iconic reunification-era fiscal instrument.
Per invariant 3, reforms are scored by what they did on each channel-separated axis, not by the party that enacted them. This fingerprint is how the policy-match engine finds historical analogues.
Explicit links are curated by the author. Inferred links are hypotheses in the library that test the same axes this policy moved — the framework's answer to "what does the data say about a policy like this?".
Ranked by axis-fingerprint overlap with this policy. Direction match bolded — those are the closest historical analogues. Shape of the match is what drives policy-outcome comparison, not the country or party label.