Policies·au_personal_income_tax_plan_2018

Personal Income Tax Plan (Stage 1/2/3) — Australia 2018

AUS·2018 – 2024·enacted 2018-06-21·Liberal-National Coalitioncandidate

What the policy did

Treasury Laws Amendment (Personal Income Tax Plan) Act 2018 legislated a seven-year three-stage personal income tax package: Stage 1 targeted low- and middle-income tax offset (LMITO); Stage 2 bracket-threshold rises from 1 July 2022; Stage 3 removal of the 37% bracket and flat 30% rate from A$45k to A$200k scheduled for 1 July 2024. Stage 2 and Stage 3 were subsequently accelerated (October 2020 budget) and Stage 3 redesigned by Labor (February 2024) before commencement.

Policy-content fingerprint — what this policy moved, on which axes

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.

intended

↓

tax progressivity

fiscal.tax_progressivity

Progressivity of the personal income tax schedule, including top marginal rates, bracket spread, and targeted credits (EITC-equivalents).

decreased · moderate

less progressive (flatter rates, compression, smaller credits)

Flattening of income-tax schedule via bracket compression and abolition of 37% bracket (as originally legislated).

Enacted by

Empirical evidence — linked hypotheses

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?".

Chilean post-Pinochet tax progressivity reforms — Concertación-era Aylwin-Frei marginal-rate increases 1990-1995, Bachelet 2014 reform raising corporate rate from 20 to 27 percent + DTA tightening, Boric 2022-2024 reform attempts — produced gradual reductions in the Chilean top-1 pretax income share by at least 1.5 percentage points over 1990-2024 vs Latin-American synthetic comparator pool, with most of the level shift concentrated in 1990-2000 rather than the recent reform attempts.

tax_inequality_chile_post_pinochet_progressivityinferred

viafiscal.tax_progressivity

INCONCLUSIVE_DATA_PENDING — insufficient pre-period coverage (years=0, donors=0)

run pending

Greek Memorandum-era tax hikes 2010-2018 (top marginal income rate raised to 45 percent, VAT hikes to 24 percent standard, ENFIA recurring property tax 2014, solidarity surcharge 2011-2019) raised the disposable-income Gini coefficient by at least 1.5 Gini-points relative to Eurozone- comparator synthetic control over the period, with the regressivity driven by VAT and property-tax incidence rather than income-tax progressivity.

tax_inequality_greece_troika_tax_hikes_2010_2018inferred

viafiscal.tax_progressivity

PARTIAL — mean_gap=+3.175, |gap|/pre_sd=3.7, p_perm=0.333 (gap below 0.5×pre_sd or placebo p≥0.10)

partial

Post-apartheid South African tax structure (top marginal income rate raised to 45 percent in 2017, capital-gains inclusion ratio raised 2012 + 2016, recurring property-tax effective burden via municipal rates) produced a measurable reduction in the South African top-1 pretax income share over 1995-2024 vs SADC synthetic comparator pool, with the recurring property-tax channel contributing more than the marginal-income-rate channel to the distributional effect.

tax_inequality_south_africa_property_tax_burdeninferred

viafiscal.tax_progressivity

INCONCLUSIVE_DATA_PENDING — insufficient pre-period coverage (years=5, donors=0)

run pending

Progressive income-tax marginal rates (up to roughly 70% top rate) have been compatible with strong growth in post-war US 1945-1980 and Nordics, falsifying extreme-Laffer-curve positions.

top_marginal_rate_growth_tradeoffinferred

viafiscal.tax_progressivity

PARTIAL — coef=+0.0006927, p=0.558 (above α=0.05); direction inconclusive

partial

Countries in the top quartile of Heritage lower-tax-burden score in 2024 have lower latest-available extreme-poverty headcount than bottom-quartile countries, consistent with free-market country policy regimes outperforming less market-oriented regimes on this outcome.

heritage_tax_burden_extreme_poverty_current_gapinferred

viafiscal.tax_progressivity

PARTIAL — gap sign/magnitude not decisive (diff=1.296, p=0.7399)

partial

Conditional on latest real GDP per capita and broad Heritage region, countries with higher Heritage lower-tax-burden score in 2024 have lower latest-available extreme-poverty headcount.

heritage_tax_burden_extreme_poverty_income_region_robustnessinferred

viafiscal.tax_progressivity

PARTIAL — controlled coefficient not decisive (coef=-1.28, p=0.2307)

partial

Countries in the top quartile of Heritage lower-tax-burden score in 2024 have higher latest-available account ownership than bottom-quartile countries, consistent with free-market country policy regimes outperforming less market-oriented regimes on this outcome.

heritage_tax_burden_account_ownership_current_gapinferred

viafiscal.tax_progressivity

REFUTED — top-vs-bottom gap has opposite sign and Welch p=2.887e-05

refuted

Conditional on latest real GDP per capita and broad Heritage region, countries with higher Heritage lower-tax-burden score in 2024 have higher latest-available account ownership.

heritage_tax_burden_account_ownership_income_region_robustnessinferred

viafiscal.tax_progressivity

REFUTED — controlled market-score coefficient has opposite sign and p=0.01161

refuted

Similar historical policies

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.

Goods and Services Tax introduction

15 percent flat personal income tax 2008

Czech super-gross-wage abolition 2021

CZE·2021