Data Sources & Methodology

Transparent documentation of all data sources, processing scripts, and methodologies used to create the charts and comparisons in Statmerica.

Data Sources

Consumer Price Index (CPI)

Year-over-year inflation rates tracking price changes in goods and services

Source

Organization: U.S. Bureau of Labor Statistics

Homepage:www.bls.gov/cpi/

Series: CUUR0000SA0

Coverage: 1980–2025

Frequency: Annual (Dec), plus current-year latest month

Credibility & Impartiality

Processing

pnpm run fetch:cpi

data/cpi.json

Attribution: Public domain

Methodology

Fetch CPI-U series from BLS
Compute December YoY for 1980–2024
Append current-year latest month YoY

Chart Usage

Inflation Rate card (YoY)

Homeownership

Quarterly Census homeownership rate; annualized with Q4 and latest quarter

Source

Organization: Federal Reserve Bank of St. Louis (FRED)

Homepage:fred.stlouisfed.org/series/RHORUSQ156N

Series: RHORUSQ156N

Coverage: 1980–2025

Frequency: Annual (Q4), plus latest quarter

Credibility & Impartiality

Processing

pnpm run fetch:homeownership

data/homeownership.json

Attribution: Public domain

Methodology

Fetch FRED RHORUSQ156N (quarterly)
Select Q4 values for 1980–2024 and compute YoY
Append latest quarter and YoY vs same quarter prior year

Chart Usage

Homeownership Rate card (YoY, Percent)

Life Expectancy at Birth (US)

Annual life expectancy in years; includes YoY percent change

Source

Organization: World Bank

Homepage:data.worldbank.org/indicator/SP.DYN.LE00.IN

Series:

Coverage: 1979–2023

Frequency: Annual

Credibility & Impartiality

Processing

pnpm run fetch:life-expectancy

data/life_expectancy.json

Attribution: World Bank Open Data

Methodology

Fetch World Bank SP.DYN.LE00.IN (USA)
Filter to 1979+ and compute YoY

Chart Usage

Life Expectancy card (YoY, Years)

Real GDP (Chained 2017 $, SAAR)

Q4 real GDP levels with YoY vs prior Q4; includes latest quarter

Source

Organization: Federal Reserve Bank of St. Louis (FRED) / BEA

Homepage:fred.stlouisfed.org/series/GDPC1

Series: GDPC1

Coverage: 1980–2025

Frequency: Annual (Q4), plus current-year latest quarter

Credibility & Impartiality

Processing

pnpm run fetch:gdp

data/gdp.json

Attribution: Public domain

Methodology

Fetch FRED GDPC1 quarterly real GDP
Select Q4 values for 1980–2024 and compute YoY
Append latest quarter and YoY vs same quarter prior year

Chart Usage

GDP Growth card (YoY, USD billions SAAR)

Federal Debt / GDP Ratio

Q4 federal Debt / GDP ratio (%), YoY vs prior Q4; includes latest quarter

Source

Organization: Federal Reserve Bank of St. Louis (FRED)

Homepage:fred.stlouisfed.org/series/GFDEGDQ188S

Series: GFDEGDQ188S

Coverage: 1980–2025

Frequency: Annual (Q4), plus current-year latest quarter

Credibility & Impartiality

Processing

pnpm run fetch:debt-to-gdp

data/debt_to_gdp.json

Attribution: Public domain

Methodology

Fetch FRED GFDEGDQ188S quarterly Debt/GDP %
Select Q4 values for 1980–2024 and compute YoY
Append latest quarter and YoY vs same quarter prior year

Chart Usage

Debt / GDP Ratio card (YoY, Percent)

Household Income

Real median household income (constant dollars) with YoY

Source

Organization: FRED (Census via FRED) + WID (P50 growth for backfill)

Homepage:fred.stlouisfed.org/series/MEHOINUSA672N

Series:

Coverage: 1979–2023

Frequency: Annual

Credibility & Impartiality

Processing

pnpm run fetch:household-income

data/household_income.json

Attribution: Public domain; backfill heuristic uses P50 growth as proxy.

Methodology

Fetch FRED real median household income (1984+)
Backfill 1979–1983 chaining P50 growth
Compute YoY on real income level

Chart Usage

Household Income card (YoY, USD)

Wages

Real average hourly earnings (production & nonsupervisory), CPI-adjusted

Source

Organization: FRED / BLS

Homepage:fred.stlouisfed.org/series/AHETPI

Series:

Coverage: 1980–2025

Frequency: Annual (Dec), plus latest month

Credibility & Impartiality

Processing

pnpm run fetch:wages

data/wages.json

Attribution: Public domain

Methodology

Fetch FRED AHETPI and CPIAUCSL (monthly)
Deflate AHE by CPI to get real hourly earnings
Use December values for 1980–2024 and compute YoY; append latest month

Chart Usage

Wages card (YoY, USD/hr)

Gas Prices (Regular, Retail)

Average retail gasoline price; annual averages with latest observation

Source

Organization: U.S. Energy Information Administration

Homepage:www.eia.gov/petroleum/gasdiesel/

Series: PET.EMM_EPMRR_PTE_NUS_DPG.M

Coverage: 1979–2025

Frequency: Annual (avg value + yoy), plus latest point

Credibility & Impartiality

Processing

pnpm run fetch:gas

data/gas_prices.json

Attribution: Public domain

Methodology

Fetch EIA gas price series (monthly/weekly)
Compute annual averages and YoY
Backfill early years from BLS if needed

Chart Usage

Gas Prices card (YoY, USD/gal)

Income Gap (P90/P50 Ratio)

Income inequality measured as ratio of 90th percentile to median income

Source

Organization: World Inequality Database (derived)

Homepage:wid.world/

Series:

Coverage: 1980–2025

Frequency: Annual

Credibility & Impartiality

Processing

pnpm run fetch:income-gap

data/income_gap.json

Attribution: Derived from WID P50/P90 income series

Methodology

Read P50/P90 USD levels
Extrapolate 2024–2025 using last 3-year growth
Compute ratio (P90/P50) and YoY

Chart Usage

Wealth/Income Gap card (YoY, Ratio)

S&P 500 Index

December closes and latest close; includes YoY % change (Stooq ^spx)

Source

Organization: Stooq

Homepage:stooq.com

Series: ^spx

Coverage: 1980–2025

Frequency: Annual (Dec), plus latest close

Credibility & Impartiality

Processing

pnpm run fetch:sp500

data/sp500.json

Attribution: Stooq free data

Methodology

Fetch Stooq ^spx (daily)
Select last trading day in December for 1980–2024
Append latest close and compute YoY vs ~same date prior year

Chart Usage

S&P 500 Index Growth card (YoY, Index)

Federal Budget Deficit (FY)

Annual deficit magnitude (outlays minus receipts), fiscal year

Source

Organization: FRED (FYFSD) — Federal Surplus or Deficit (-), Fiscal Year

Homepage:fred.stlouisfed.org/series/FYFSD

Series:

Coverage: 1979–2024

Frequency: Annual (FY)

Credibility & Impartiality

Processing

pnpm run fetch:deficit

data/deficit.json

Attribution: Federal Reserve Bank of St. Louis

Methodology

Fetch FRED FYFSD annual surplus/deficit (fiscal year, billions)
Convert to positive deficit magnitudes (absolute value)
Compute YoY on deficit level

Chart Usage

Federal Deficit card (YoY, USD billions)

Unemployment Rate (U-3, SA)

Monthly unemployment rate stored as December values plus latest month; includes YoY.

Source

Organization: U.S. Bureau of Labor Statistics

Homepage:www.bls.gov/cps/

Series: LNS14000000

Coverage: 1980–2025

Frequency: Monthly (stored as annual Dec + latest)

Credibility & Impartiality

Processing

pnpm run fetch:unemployment

data/unemployment.json

Attribution: Public domain

Methodology

Fetch BLS CPS unemployment rate series (LNS14000000, SA)
Select December values to form annual series (1980–2024)
Append current-year latest month vs same month prior year

Chart Usage

Unemployment Rate card (YoY, Percent)

Data Processing Scripts

fetch:nasdaq

Fetches NASDAQ Composite from FRED; builds annual Dec + latest YoY

Command

pnpm run fetch:nasdaq

File

scripts/fetch-sp500.mjs

Parameters

--series NASDAQCOM (default)
--series SP500

Environment Variables

FRED_API_KEY (required)

Output

data/sp500.json

fetch:cpi

Fetches Consumer Price Index data from BLS Public API

Command

pnpm run fetch:cpi

File

scripts/fetch-cpi.mjs

Parameters

--series cuur|cusr (default: cuur)

Environment Variables

BLS_API_KEY (optional, increases rate limits)

Output

data/cpi.json

fetch:gas

Fetches U.S. regular gasoline prices from EIA (with BLS backfill)

Command

pnpm run fetch:gas

File

scripts/fetch-gas-prices.mjs

Environment Variables

EIA_API_KEY (required)
BLS_API_KEY (optional for backfill)

Output

data/gas_prices.json

wid:extract:income

Extracts US income data (P50, P90) from WID CSV files

Command

pnpm run wid:extract:income

File

scripts/wid-extract-income-us.mjs

Parameters

--dir PATH (default: data/wid)
--debug

Output

data/us_income_p50.csv, data/us_income_p90.csv

fetch:income-gap

Builds income gap ratios and YoY changes from P50/P90 CSVs

Command

pnpm run fetch:income-gap

File

scripts/fetch-income-gap.mjs

Output

data/income_gap.json

fetch:deficit

Aggregates Treasury MTS receipts/outlays into annual federal deficit

Command

pnpm run fetch:deficit

File

scripts/fetch-deficit.mjs

Output

data/deficit.json

fetch:unemployment

Fetches unemployment rate (BLS CPS) and computes Dec YoY

Command

pnpm run fetch:unemployment

File

scripts/fetch-unemployment.mjs

Environment Variables

BLS_API_KEY (optional, increases rate limits)
--series lns (default)

Output

data/unemployment.json

fetch:gdp

Fetches real GDP (GDPC1) and builds annual Q4 + latest quarter

Command

pnpm run fetch:gdp

File

scripts/fetch-gdp.mjs

Output

data/gdp.json

fetch:debt-to-gdp

Fetches Debt/GDP ratio (GFDEGDQ188S) and builds annual Q4 + latest

Command

pnpm run fetch:debt-to-gdp

File

scripts/fetch-debt-to-gdp.mjs

Output

data/debt_to_gdp.json

fetch:household-income

Builds Household Income: real median HH income with 1979–83 backfill

Command

pnpm run fetch:household-income

File

scripts/fetch-household-income.mjs

Output

data/household_income.json

fetch:wages

Computes Real Wages: deflates AHETPI by CPI; Dec + latest YoY

Command

pnpm run fetch:wages

File

scripts/fetch-wages.mjs

Environment Variables

FRED_API_KEY (optional)

Output

data/wages.json

fetch:homeownership

Fetches Homeownership Rate (RHORUSQ156N), annualizes by Q4, adds latest quarter

Command

pnpm run fetch:homeownership

File

scripts/fetch-homeownership.mjs

Output

data/homeownership.json

fetch:life-expectancy

Fetches Life Expectancy at birth (World Bank) and computes YoY

Command

pnpm run fetch:life-expectancy

File

scripts/fetch-life-expectancy.mjs

Output

data/life_expectancy.json

Data Update Process

How to refresh data sources and maintain data quality

Update Workflow

Run pnpm run fetch:cpi to update inflation data from BLS
Update WID CSV files in data/wid/ from latest WID exports
Run pnpm run wid:extract:income to extract P50/P90 data
Run pnpm run fetch:income-gap to compute income gap metrics
Verify data integrity and rebuild application

Data Quality

All raw data sources are preserved in their original format
Processing scripts are deterministic and repeatable
Data transformations are documented and version controlled
Extrapolations for future years are clearly marked and explained