Finance Charts Methodology and Data Sources

Finance Charts

How Lumen Calculator turns official finance data into reproducible charts without outsourcing authoritative calculations to an AI model.

Registry reviewed:

Data workflow

  1. Record the official publisher, series identifier, direct dataset, retrieval date, reuse terms and known limitations.
  2. Keep source observations separate from derived output and transform them with deterministic, tested functions.
  3. Detect missing or partial periods and omit any aggregate that is not complete.
  4. Compute every quantitative finding before explanatory text is drafted.
  5. Require each narrative number to reference a current computed metric; failed checks stop publication.

Common calculations

Inflation adjustment: nominal value × CPI in the stated base period ÷ CPI in the observation period.

Ratio: numerator ÷ denominator, with compatible dates and units, expressed in the labelled unit.

Spread or ex-post real rate: first percentage rate minus second percentage rate. A cash-rate-minus-CPI spread is an approximation and is not an expected real interest rate.

Frequency alignment: values are joined only after applying the chart’s documented period convention. Complete-period checks run before annual or quarterly aggregates are emitted.

Source and licence register

Series and publisherFrequencyCoverageLicence statusAttribution
Consumer Price Index, All groups, AustraliaAustralian Bureau of Statisticsquarterly1948-Q3–2026-Q2commercial_with_attributionApproved for publication under recorded termsSource: Australian Bureau of Statistics, Consumer Price Index, Australia, CC BY 4.0.
Full-time adult average weekly ordinary time earnings, personsAustralian Bureau of Statisticshalf_yearly1994-S2–2025-S2commercial_with_attributionApproved for publication under recorded termsSource: Australian Bureau of Statistics, Average Weekly Earnings, Australia, CC BY 4.0.
Cash Rate Target, monthly averageReserve Bank of Australiamonthly1990-08–2026-06commercial_with_restrictionsApproved for publication under recorded termsSource: RBA 2026. The RBA does not endorse LumenCalculator or this use.
Australian resident individual income tax ratesAustralian Taxation Officefinancial_year1983-84–2025-26open_commercialApproved for publication under recorded termsSource: Australian Taxation Office. No ATO or Commonwealth endorsement is implied.
HELP compulsory repayment minimum thresholdAustralian Taxation Officefinancial_year2019-20–2026-27open_commercialApproved for publication under recorded termsSource: Australian Taxation Office. No ATO or Commonwealth endorsement is implied.
HELP policy and indexation guidanceAustralian Government Department of Educationirregular–2026-08-02commercial_with_attributionApproved for publication under recorded terms© Commonwealth of Australia, Department of Education, used under CC BY 4.0.
Concessional contributions general capAustralian Taxation Officefinancial_year2007-08–2025-26open_commercialApproved for publication under recorded termsSource: Australian Taxation Office. No ATO or Commonwealth endorsement is implied.

AI-assisted explanations

The model receives chart definitions, methodology, verified source metadata, computed metrics and explicit limitations. It does not author the underlying calculations. Structured metric references and numeric-claim validation are mandatory before publication, and unchanged inputs reuse a content-addressed cache.

Corrections and review

Charts display their source retrieval and last-updated dates. If a source changes, the derived data and narrative cache become stale and must be rebuilt and revalidated. Contact Lumen Calculator to report a possible correction.

Finance Charts provide general educational information, not personal financial, tax or legal advice.