Progressivity of the personal income tax schedule, including top marginal rates, bracket spread, and targeted credits (EITC-equivalents).
Belastingherziening Oort, effective 1 January 1990, flattened personal income-tax schedule to three brackets (7.05% / 50% / 60%), merged employee social-insurance contributions into the first bracket, broadened the base by limiting deductions, and raised the basic threshold. Substantial simplification of Dutch income-tax architecture; precursor to 2001 Wet IB reform.
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.