General government spending as share of GDP, excluding transfers already captured under fiscal.transfer_expansion to avoid double-counting.
Rule of law as institutional substrate — contract enforcement, judicial independence, equal treatment before the law. Upstream of most other axes.
Ratification by the Bundestag and Bundesrat of the Treaty on Stability, Coordination and Governance in the Economic and Monetary Union (TSCG, signed March 2012, often called the Fiscal Compact) which required signatory states to enshrine a balanced-budget rule in national (preferably constitutional) law with a structural deficit ceiling of 0.5% GDP (1.0% for low-debt states) and automatic correction mechanism. Germany already had the Schuldenbremse and actively promoted the treaty across the euro area.
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.