Macro economics, walked from headline GDP to policy-school choice.

The expenditure-versus-production-versus-income approach: GDP can be measured three ways which should-but-don't-always reconcile. Expenditure approach: C + I + G + (X-M) — consumption, investment, government, net exports. Production approach: gross-value-added by sector. Income approach: wages + profits + indirect taxes - subsidies. Statistical discrepancy between the three approaches typically runs 1-3% in well-measured economies, much larger in lower-capacity statistical-systems. Sectoral breakdown: agricultural-share is now under 5% in most developed economies, services-share over 70% in most developed economies; manufacturing-share peaks at 20-30% in successfully-industrialising economies (China, Korea historical, Germany, Japan); manufacturing-share over 25% is the rare achievement (Germany, Czech Republic, China, South Korea, Slovenia).

The PPP measurement cycle and limitations: ICP rounds occur every 6-7 years (2005, 2011, 2017, 2021 reference years); intermediate years use national-accounts deflators to bridge. The 2017 round was the most-rigorous to date; the 2021 round results published 2024. Methodological caveats: PPP captures consumer baskets reasonably well but services-tradability and quality-adjustment remain hard; informal-economy size affects developing-country PPP estimates substantially; Chinese data have particular debate over reliability. Per-capita PPP rather than total PPP is the welfare-relevant statistic: top per-capita-PPP includes Luxembourg, Singapore, Ireland, Norway, Switzerland, Qatar, UAE, US, Denmark, Iceland; bottom includes much of sub-Saharan Africa, Afghanistan, Yemen, Burundi, Central African Republic. The platform documents the full per-capita-PPP series with caveats per data round.

The Taylor Rule framework articulated by John Taylor 1993 has become the implicit policy-rate-setting benchmark globally: nominal interest rate = neutral real rate + inflation + 0.5 × (inflation - target) + 0.5 × (output gap). Most central banks deviate from strict Taylor Rule outputs but remain within explainable distance; the post-2008 zero-lower-bound period and the post-2021 inflation-shock policy-tightening cycle have stress-tested the framework. Forward guidance: explicit communication of policy-path (Fed dot-plot, ECB Governing Council statements, BoJ Yield Curve Control commitments) is now a complementary policy lever to the policy rate itself.

Quantitative easing and quantitative tightening: the unconventional toolset originated with the BoJ (post-2001) and was deployed at massive scale by the Fed (post-2008 USD 4.5T balance sheet peak, expanded further to USD 9T post-2020), the BoE (post-2009), the ECB (post-2014 OMT and PSPP), the BoJ (post-2013 QQE plus YCC). Post-2022, most central banks have embarked on QT — passive runoff (Fed, ECB) or active sales (BoE) reducing balance sheets. Emerging-market constraint: when the Fed tightens, EM central banks typically must follow to defend currencies (or accept depreciation); this "dollar dominance" channel is the most-watched cross-border policy-spillover mechanism. Currency-swap-line networks: Fed standing swaps with ECB, BoE, BoJ, SNB, BoC; FIMA repo facility for foreign central banks — provide dollar-liquidity backstops.

Primary balance versus headline balance: the headline balance includes interest-payments on existing debt; the primary balance excludes them and measures "new borrowing minus debt-service". Debt-sustainability mathematics depend critically on the primary balance versus the (real-rate minus growth) differential. The (r - g) condition: when real growth (g) exceeds real interest cost (r), debt-to-GDP falls automatically with primary balance at zero; when r exceeds g, primary surplus is required to stabilise debt. Post-2008 to 2021 the developed world experienced sustained r-less-than-g, allowing fiscal flexibility; post-2022 rate-rise has reset the calculus.

Sovereign credit and market-access: credit-rating agencies (S&P, Moody's, Fitch, plus Chinese Dagong, Indian CARE / ICRA) score sovereign debt; AAA / Aaa ratings are now held by a small group (Germany, Netherlands, Switzerland, Norway, Sweden, Denmark, Australia, Singapore, Canada at S&P, plus a few smaller). The US has been AA+ at S&P since 2011 and Moody's downgraded one notch in 2023; UK was downgraded post-2016 and post-2022; France lost AAA in 2012; Germany retains AAA across all three. Investment-grade-versus-junk threshold (BBB-/Baa3) is the binding constraint for institutional ownership; sovereigns near this line (Italy, several emerging markets) carry binding risk. Sovereign default and restructuring: post-2008 episodes — Greece 2012, Argentina multiple, Venezuela, Lebanon 2020, Sri Lanka 2022, Zambia, Ghana, Ethiopia, Pakistan distressed, Egypt support-programme — with IMF EFF / RFI programmes and Common Framework restructuring vehicles.

Reserve currencies and the dollar dominance: USD is the world's primary reserve currency, comprising approximately 58% of allocated FX reserves (IMF COFER data, declining slowly from 70%+ pre-2000); EUR around 20%; JPY around 5-6%; GBP around 5%; CNY around 2-3% (rising slowly); CAD, AUD, CHF making up the rest. Petrodollar recycling: oil-export-economies invest USD reserves in US Treasuries plus diversification (sovereign wealth funds — Saudi PIF, UAE ADIA / Mubadala, Kuwait KIA, Norway NBIM the largest). Reserve-adequacy metrics: imports-cover (3-month minimum traditional), short-term-debt-cover (Greenspan-Guidotti rule), broader IMF reserve-adequacy metric.

FX intervention and emerging-market dynamics: emerging-market central banks routinely intervene to lean against currency pressure, with intervention coordinated through the BIS Triennial Central Bank Survey context and bilateral consultation. Carry-trade flows — investors borrowing low-yield currencies (JPY, CHF historically) to invest in high-yield currencies (TRY, BRL, ZAR, MXN historically) — drive substantial volatility cycles, with sudden-reversals during risk-off episodes. Currency-swap lines: as noted under monetary policy, the Fed standing-swaps plus FIMA-repo provide the dollar-funding backstop for major central banks; emerging-market central banks rely on bilateral swap lines (e.g. PBoC bilateral renminbi-swap network with over 40 counterparts) plus IMF facilities. Crypto and stablecoin role: USD-stablecoins (USDC, USDT) are emerging as a de-facto dollar-substitute layer in some emerging markets with FX scarcity, though regulatory treatment is highly variable.

The post-2021 inflation episode: developed-economy CPI peaked at 9-10%+ in 2022 (US, UK, Germany; double-digits in some EU countries due to gas-prices); the policy-tightening cycle returned headline CPI to 2-4% range by 2024; core CPI lagged but converged. The structural-versus-cyclical debate: aging demographics (deflationary), de-globalisation (inflationary), energy-transition capex (inflationary near-term, deflationary long-term), AI-productivity (uncertain, possibly deflationary), labour-market tightness (wage-Phillips). Inflation expectations anchoring: Michigan Survey, BoE expectations survey, ECB CES, NY Fed survey of consumer expectations — central banks now monitor the medium-term-anchored measures closely; the post-2021 episode threatened de-anchoring but largely held.

Hyperinflation cases: the IMF and academic literature (notably Hanke-Krus historical hyperinflation table) catalogues the major historical episodes — Hungary 1946 (the worst monthly rate in history), Yugoslavia 1994, Zimbabwe 2008, Venezuela 2018-2020, Sudan 2021-2023, Lebanon 2019-current, Argentina recurring (the 2023 election-cycle stabilisation programme is the latest reset attempt). Currency-substitution and dollarisation typically accompany hyperinflation; indexation (UF in Chile, sovereign-bonds-with-CPI-indexation in many countries) is the structural-inflation adaptation; price controls and queues the policy-failure mode. Asset-price inflation versus consumer-price inflation is the recurring policy-debate — housing inflation in particular is captured imperfectly in CPI (owner-equivalent rent versus market rent issues; Indian CPI has different housing weight than US).

Underemployment, U-6, NEET: the ILO U1-U6 unemployment-broadness ladder includes U-6 in the US (broadest measure including discouraged-and-marginally-attached plus part-time-for-economic-reasons) typically running 7-10%. NEET (not-in-employment-education-or-training) for youth 15-24: the OECD-and-ILO measure of labour-market detachment; ranges from under 5% (Iceland, Netherlands, Sweden best) through 10-15% (most developed economies) to over 25% in much of Sub-Saharan Africa, Middle East, and parts of Latin America. Informal-sector share: ILO estimates approximately 60% of global employment is informal, ranging from under 10% in most OECD countries to over 80% in much of Sub-Saharan Africa and South Asia — a binding constraint on tax-base, social-insurance coverage, and productivity.

Wage and labour-share dynamics: labour share of GDP has declined in most developed economies since 1980, from around 65-70% to around 55-60% (the "Karabarbounis-Neiman decline"), with multiple structural drivers (globalisation, technology, market-concentration, decline of unionisation). Minimum wage: levels vary enormously — statutory floor in most OECD economies (US federal stuck at USD 7.25 with state/city floors much higher; UK National Living Wage GBP 11.44; German Mindestlohn EUR 12.41; French SMIC EUR 11.65; Swiss Geneva canton CHF 24); collective-bargaining-determined in Nordic countries; minimum-wage ladders by sector and skill in much of Asia. Labour-market institutions: employment-protection-legislation (OECD EPL index), wage-bargaining-coverage, active-labour-market-programmes, unemployment-insurance generosity vary widely. The platform indexes EPL stringency, ALMP spend, UI replacement-rates.

Remittance flows are a major BoP component for many developing economies that is often under-discussed in financial-headlines: India received over USD 125B in 2024 (the world's largest), followed by Mexico, China, Philippines, France, Pakistan, Bangladesh, Egypt, Nigeria, Vietnam. As a share of GDP, remittances exceed 20% in Lebanon, Kyrgyzstan, Tajikistan, Tonga, Samoa, Honduras, El Salvador, Nepal — making these economies acutely sensitive to the labour-market conditions in their major host countries. The World Bank Migration and Development Brief tracks the cost-of-remitting (target: under 3% per UN SDG 10.c.1; current-global-average around 6%); Indian PSU-bank remittance-corridor pricing tends below the global average.

FDI flows and reshoring: UNCTAD World Investment Report tracks global FDI flows (around USD 1.3-1.5T annually pre-pandemic; volatile post-2020). Major FDI-recipient economies: US, China, Hong Kong (transit), Singapore, Brazil, India, UK, Germany, Australia, Canada. Reshoring / friend-shoring / nearshoring: post-2018 US-China tensions plus post-2020 supply-chain shocks have driven measurable shift — Mexican FDI inflows (nearshoring beneficiary), Indian PLI-driven inflows in electronics / pharma / chemicals, Vietnamese / Indonesian / Malaysian FDI growth (China-plus-one strategy), Polish / Czech / Romanian European-friendshoring beneficiaries. Errors and omissions: the residual that captures unrecorded flows can be substantial — for many emerging markets, persistently negative E&O suggests capital flight; for the US, persistent positive E&O captured the "dark matter" debate of the 2000s.

Banking-system health metrics: NPL ratios (non-performing-loan share of total loans) range from under 1% in best-managed systems (US, UK, Australia, much of Asia) through 3-5% in most developed-EU systems through 5-15% in stressed peripheral-EU markets (Italy, Greece historical) and Indian PSU-banks pre-2018 reform; post-IBC reform Indian NPL ratios have improved sharply. Capital ratios: most major banks now run CET1 of 12-16%; well above Basel minimum. Liquidity-coverage ratio (LCR) and net-stable-funding ratio (NSFR): post-2008 liquidity standards now bind globally. Stress testing: Fed CCAR / DFAST since 2009, ECB EBA stress tests, BoE FPC scenarios, RBA / RBI / BoJ analogues.

Shadow banking, NBFCs, and the stress-points: the post-2008 regulatory tightening in banks pushed substantial activity into less-regulated channels — money-market funds (post-2014 SEC reform, post-2020 Fed Money Market Mutual Fund Liquidity Facility), open-end credit-fund liquidity-mismatches (the Woodford Equity Income episode 2019, the 2022 UK LDI / gilt episode), private credit (now over USD 2T globally; less-regulated than banks; rapid post-2022 expansion), Indian NBFCs (the IL&FS 2018 episode triggered substantial reform; DHFL, Reliance Capital follow-on stress; new SBR framework 2022+). Cryptocurrency and stablecoins: the 2022 Terra / Luna collapse, FTX failure, Celsius / Voyager bankruptcies; ongoing regulatory framework-building (EU MiCA effective 2024, US fragmented state-level plus pending federal, UK FSMA 2023 financial-promotions regime).

Multidimensional poverty: the UNDP Global MPI complements the World Bank monetary-poverty measure (USD 2.15/day extreme-poverty line, 2017 PPP; revised periodically) by capturing health, education, and standard-of-living deprivations. Extreme poverty: the global rate fell from around 36% in 1990 to around 9% pre-pandemic; the post-2020 reversal added an estimated 70-100M back into extreme poverty (the World Bank's revised picture). Geographic concentration: extreme poverty is now concentrated in Sub-Saharan Africa (around 60% of the global total) and South Asia (around 25%), with conflict-affected states (DRC, Yemen, Afghanistan, Sudan, South Sudan, Syria, Somalia) contributing disproportionately.

Intergenerational mobility: the "Great Gatsby Curve" (Krueger 2012, Corak research) shows higher inequality correlates with lower mobility; the most-mobile economies (Denmark, Norway, Finland, Canada) have around 40-50% Inter-generational Earnings Elasticity (IGE) versus around 50-60% in the US, UK and many emerging markets. Wealth versus income inequality: wealth Gini is consistently higher than income Gini everywhere; the top-1% wealth-share runs around 30-40% in most developed economies; Credit Suisse-now-UBS Global Wealth Report tracks the global picture with HNW (USD 1M+) and UHNW (USD 50M+) population data. Tax-and-transfer effects: market-Gini versus disposable-Gini differs by 10-20 points in most developed economies (taxes and transfers are the dominant flattening force); much smaller differential in many emerging markets where the tax-base and welfare-state are smaller.

The post-2008 framework debate: the financial-crisis exposed limitations in pre-crisis New-Keynesian DSGE-models (which had de-emphasised financial-sector frictions); subsequent work has emphasised "financial-frictions" modules and macroprudential-policy instruments. The post-2021 inflation episode reignited debates on the Phillips Curve, the supply-shock-versus-demand-shock contribution to inflation, the right-distance-from-NAIRU. Modern Monetary Theory (MMT): post-Wynne Godley sectoral-balances and Warren Mosler / Stephanie Kelton popularisation; argues sovereign-currency-issuers face inflation-not-debt-as-the-binding-constraint — influential in some progressive policy-circles, sceptically received by mainstream central-bankers; the UK 2022 mini-budget episode and the 2021-23 inflation surge have been read very differently by MMT-proponents and orthodox-economists.

Behavioural economics: the Kahneman-Tversky-Thaler tradition (Nobel 2002, 2017); prospect-theory, mental-accounting, choice-architecture, nudge-policy. Development economics: from Lewis dual-economy through Solow growth-model through endogenous-growth (Romer, Lucas) through institutions-matter (North, Acemoglu-Robinson Why Nations Fail / Narrow Corridor) through randomised-evaluation (Banerjee-Duflo-Kremer Nobel 2019). Heterodox traditions: ecological economics (Daly, Costanza), feminist economics (Folbre, Power), Marxist-revival (Harvey, Mason), Modern Money plus Job-Guarantee (Wray, Tcherneva). The platform's economics explainers credit the framework explicitly so users can locate any policy-debate within the contest of schools rather than treat any particular framework as default-neutral.