c1d6b0b9f8
Created new US-Inflation data directory with: - 945 monthly CPI-U observations from FRED/BLS (Jan 1947 - Aug 2025) - Comprehensive metadata documentation with methodology - README with source research and justification - UPDATES.md change log and update procedures - RESOURCES.md with data sources and API access - Structure mirrors existing COVID wastewater dataset Data source: FRED Series CPIAUCSL (CPI for All Urban Consumers, Seasonally Adjusted) Update frequency: Monthly (mid-month BLS releases) 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
169 lines
6.6 KiB
Markdown
169 lines
6.6 KiB
Markdown
# U.S. Consumer Price Index (CPI) - Inflation Data
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## Metadata
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**Data Source**: Federal Reserve Economic Data (FRED) / U.S. Bureau of Labor Statistics (BLS)
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**Primary URL**: https://fred.stlouisfed.org/series/CPIAUCSL
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**Direct CSV**: https://fred.stlouisfed.org/graph/fredgraph.csv?id=CPIAUCSL&cosd=1947-01-01
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**BLS Series**: CPIAUCSL (Consumer Price Index for All Urban Consumers: All Items in U.S. City Average)
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**Update Frequency**: Monthly (released mid-month following data month at 8:30 AM ET)
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**Last Updated**: 2025-10-07
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**Coverage**: United States, January 1947 - Present
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**License**: Public domain (U.S. government data)
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## Data Description
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### Primary Metrics
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**Consumer Price Index (CPI-U)**: Measures changes in the price level of a weighted average market basket of consumer goods and services purchased by households
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- **Unit**: Index value (1982-1984 = 100 baseline)
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- **Population Coverage**: All Urban Consumers (approximately 93% of U.S. population)
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- **Seasonally Adjusted**: Yes
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- **Base Period**: 1982-1984 = 100
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### Data Format
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The FRED dataset provides:
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- `observation_date`: Month identifier (YYYY-MM-DD format, first day of month)
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- `CPIAUCSL`: CPI-U index value (seasonally adjusted)
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### Calculation Methodology
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- **Index Calculation**: Laspeyres price index formula
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- **Basket Composition**: ~80,000 items across 8 major categories:
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- Food and beverages
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- Housing
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- Apparel
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- Transportation
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- Medical care
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- Recreation
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- Education and communication
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- Other goods and services
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- **Weight Updates**: Basket weights updated every 2 years based on Consumer Expenditure Survey
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- **Geographic Coverage**: 75 urban areas across the United States
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## Key Insights from Data
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### Current Status (August 2025)
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- **Latest Reading**: 323.364 (August 2025)
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- **Year-over-Year Inflation**: Approximately 2.5% (based on 12-month change)
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- **Trend**: Moderating from 2022-2023 peaks, stabilizing near Federal Reserve target
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### Historical Context
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- **Post-WWII Low**: 21.480 (January 1947)
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- **2022-2023 Peak**: 317.603 (December 2024)
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- **Total Increase**: 1,404% from 1947 to 2025 (78-year period)
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- **Average Annual Inflation**: ~3.5% over full period
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### Major Inflation Episodes
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- **1970s Stagflation**: Double-digit inflation (peak 14.8% in 1980)
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- **Great Moderation** (1990s-2000s): Stable ~2-3% annual inflation
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- **Great Recession** (2008-2009): Brief deflationary period
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- **COVID-19 Response** (2021-2023): Rapid inflation surge to 9.1% (June 2022)
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- **Current Period** (2024-2025): Gradual return to ~2% target
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### Inflation Rate Calculation
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To calculate year-over-year inflation rate:
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```
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Inflation Rate = ((CPI_current - CPI_12months_ago) / CPI_12months_ago) × 100
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```
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Example (August 2025):
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- Current: 323.364
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- One year ago (Aug 2024): ~315.5
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- Inflation: ((323.364 - 315.5) / 315.5) × 100 ≈ 2.5%
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## Data Sources & Alternative Access
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### Primary Sources
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1. **FRED (Federal Reserve Economic Data)**: https://fred.stlouisfed.org/series/CPIAUCSL
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2. **BLS Official CPI Page**: https://www.bls.gov/cpi/
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3. **BLS Data Tools**: https://data.bls.gov/timeseries/CPIAUCSL
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### Related CPI Series
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- **CPILFESL**: CPI for All Urban Consumers: All Items Less Food & Energy (Core CPI)
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- **CPIAUCNS**: CPI-U Not Seasonally Adjusted
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- **CPIENGSL**: CPI for Energy
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- **CPIFABSL**: CPI for Food and Beverages
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### API Access
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- **FRED API**: https://fred.stlouisfed.org/docs/api/fred/
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- Requires free API key
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- JSON and XML formats
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- Comprehensive time series access
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- **BLS Public Data API**: https://www.bls.gov/developers/
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- Free tier: 500 queries/day
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- JSON format
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- Multiple series access
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## Usage Notes
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### Data Quality
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- **Reliability**: Gold standard for U.S. inflation measurement
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- **Frequency**: Monthly updates (mid-month release)
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- **Timeliness**: Published ~2 weeks after month end
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- **Revisions**: Minimal - typically only seasonal adjustment factors revised
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- **Completeness**: 945 monthly observations (1947-2025)
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### Interpretation Guidelines
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1. **Index vs. Rate**: CPI is an index; inflation rate is the percentage change
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2. **Compounding Effects**: Small annual rates compound significantly over decades
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3. **Purchasing Power**: CPI of 100 in 1984 requires ~323 today for equivalent purchasing power
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4. **Real vs. Nominal**: Use CPI to adjust nominal dollars to real (inflation-adjusted) values
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5. **Base Period**: 1982-1984 average = 100 baseline
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### Limitations
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- **Substitution Bias**: Fixed basket doesn't capture consumer substitution behavior
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- **Quality Changes**: Difficult to adjust for product quality improvements
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- **New Products**: Slow to incorporate new goods and services
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- **Geographic Variation**: National average masks regional differences
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- **Population Coverage**: Excludes rural households (~7% of population)
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## Related Substrate Components
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**Claims Supported:**
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- CPI as authoritative measure of inflation and purchasing power
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- Federal Reserve monetary policy effectiveness
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- Impact of fiscal/monetary policy on price levels
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**Problems Addressed:**
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- Economic planning and policy-making requiring accurate inflation data
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- Wage and benefit adjustments (COLAs)
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- Real return calculations for investments
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**Solutions Enabled:**
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- Inflation-adjusted economic analysis
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- Cost of living comparisons across time periods
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- Monetary policy decision-making
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## Data Processing Notes
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The accompanying CSV file (`CPI-US-Monthly-1947-2025.csv`) contains:
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- FRED series CPIAUCSL (CPI-U seasonally adjusted)
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- Monthly observations from January 1947 through August 2025
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- Index values with 3 decimal place precision
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- ISO 8601 date format (YYYY-MM-DD)
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## Use Cases
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This dataset supports:
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- **Economic Research**: Historical inflation analysis and forecasting
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- **Policy Analysis**: Federal Reserve and Treasury decision-making evaluation
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- **Financial Planning**: Real return calculations, retirement planning
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- **Wage Negotiations**: COLA adjustments based on CPI changes
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- **Academic Research**: Macroeconomic studies and modeling
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- **Substrate Integration**: Supporting Claims, Arguments, and economic Models with authoritative data
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## References
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1. BLS CPI Overview: https://www.bls.gov/cpi/overview.htm
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2. BLS CPI FAQ: https://www.bls.gov/cpi/questions-and-answers.htm
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3. FRED CPIAUCSL Series: https://fred.stlouisfed.org/series/CPIAUCSL
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4. BLS Handbook of Methods (Chapter 17 - CPI): https://www.bls.gov/opub/hom/cpi/
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5. Federal Reserve Inflation Targeting: https://www.federalreserve.gov/faqs/economy_14400.htm
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---
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**Dataset Purpose**: Provide authoritative, comprehensive U.S. inflation data to support economic analysis, policy evaluation, and real-value calculations within the Substrate knowledge system.
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