---
title: FRED Data
description: Understanding FRED's data structure and organization
icon: 'database'
---
# FRED Data Structure
FRED (Federal Reserve Economic Data) contains over 800,000 economic time series with a well-organized hierarchical structure.
## Data Hierarchy
```mermaid
graph TD
A[FRED Root] --> B[Categories]
B --> C[Subcategories]
C --> D[Series]
D --> E[Observations]
B --> F[Releases]
F --> D
D --> G[Tags]
```
## Core Entities
### Series
A series is a single economic indicator tracked over time.
<ParamField path="series_id" type="string" required>
Unique identifier (e.g., "GDP", "UNRATE", "DFF")
</ParamField>
<ParamField path="title" type="string">
Full descriptive name
</ParamField>
<ParamField path="observation_start" type="date">
Date of first available data point
</ParamField>
<ParamField path="observation_end" type="date">
Date of most recent data point
</ParamField>
<ParamField path="frequency" type="string">
Data collection interval: Daily, Weekly, Monthly, Quarterly, Annual
</ParamField>
<ParamField path="units" type="string">
Measurement units (Dollars, Percent, Index, etc.)
</ParamField>
<ParamField path="seasonal_adjustment" type="string">
SA (Seasonally Adjusted), NSA (Not Seasonally Adjusted), SAAR
</ParamField>
<ParamField path="popularity" type="integer">
Usage ranking from 1-100
</ParamField>
**Example Series:**
```json
{
"id": "UNRATE",
"title": "Unemployment Rate",
"observation_start": "1948-01-01",
"observation_end": "2024-09-01",
"frequency": "Monthly",
"frequency_short": "M",
"units": "Percent",
"seasonal_adjustment": "Seasonally Adjusted",
"popularity": 95,
"notes": "The unemployment rate represents..."
}
```
### Observations
Individual data points within a series.
```json
{
"observations": [
{
"date": "2024-09-01",
"value": "4.2",
"realtime_start": "2024-10-04",
"realtime_end": "2024-10-04"
},
{
"date": "2024-08-01",
"value": "4.3",
"realtime_start": "2024-09-06",
"realtime_end": "2024-09-06"
}
]
}
```
### Categories
Hierarchical organization of related series.
<CardGroup cols={2}>
<Card title="Money, Banking & Finance" icon="dollar-sign">
32991 - Interest rates, exchange rates, monetary aggregates
</Card>
<Card title="Population, Employment & Labor" icon="users">
10 - Demographics, employment, wages
</Card>
<Card title="Production & Business Activity" icon="industry">
1 - GDP, industrial production, capacity utilization
</Card>
<Card title="Prices" icon="tag">
32455 - Inflation, CPI, PPI, import/export prices
</Card>
<Card title="International Data" icon="globe">
32263 - Global economic indicators
</Card>
<Card title="U.S. Regional Data" icon="map">
3008 - State and metro area statistics
</Card>
</CardGroup>
### Releases
Scheduled data publications from source agencies.
```json
{
"id": 50,
"realtime_start": "2024-10-01",
"realtime_end": "2024-10-01",
"name": "Employment Situation",
"press_release": true,
"link": "https://www.bls.gov/news.release/empsit.htm"
}
```
### Tags
Categorical descriptors for discovery and filtering.
**Tag Categories:**
- **Geographic**: usa, state, nation, county, msa
- **Frequency**: daily, weekly, monthly, quarterly, annual
- **Source**: bls, bea, census, frb, oecd
- **Topic**: employment, gdp, inflation, interest rate
- **Seasonal Adjustment**: sa, nsa, saar
## Data Types
### Economic Indicators
<Tabs>
<Tab title="Labor Market">
- Unemployment Rate (UNRATE)
- Nonfarm Payrolls (PAYEMS)
- Labor Force Participation (CIVPART)
- Initial Jobless Claims (ICSA)
- Average Hourly Earnings (CES0500000003)
</Tab>
<Tab title="Production">
- Gross Domestic Product (GDP)
- Industrial Production (INDPRO)
- Capacity Utilization (TCU)
- Manufacturing Output (IPMAN)
- Retail Sales (RSXFS)
</Tab>
<Tab title="Prices">
- Consumer Price Index (CPIAUCSL)
- Core CPI (CPILFESL)
- Producer Price Index (PPIACO)
- PCE Price Index (PCEPI)
- Import Price Index (IR)
</Tab>
<Tab title="Financial">
- Federal Funds Rate (DFF)
- 10-Year Treasury (DGS10)
- S&P 500 (SP500)
- Exchange Rates (DEXUSEU)
- M2 Money Supply (M2SL)
</Tab>
</Tabs>
### Frequency Types
| Frequency | Code | Typical Use Cases | Example |
|-----------|------|-------------------|---------|
| Daily | d | Financial markets, rates | Fed Funds Rate |
| Weekly | w | Claims, surveys | Initial Claims |
| Biweekly | bw | Specific surveys | Retail sales surveys |
| Monthly | m | Most indicators | Unemployment, CPI |
| Quarterly | q | GDP, accounts | GDP, Corporate Profits |
| Semiannual | sa | Some surveys | Business outlook |
| Annual | a | Demographics, some surveys | Population |
### Units and Scaling
<Warning>
**Critical: Always check units and scaling**
Values may be expressed as:
- Raw numbers (e.g., persons employed)
- Thousands or millions (e.g., GDP in billions)
- Index values (e.g., CPI with base year)
- Percentages (e.g., unemployment rate)
- Rates (e.g., annual rate)
</Warning>
Common unit types:
```json
{
"units": "Billions of Dollars",
"units": "Percent",
"units": "Index 1982-1984=100",
"units": "Thousands of Persons",
"units": "Index 2012=100",
"units": "Millions of Dollars"
}
```
## Data Transformations
### Available Transformations
| Transformation | Code | Formula | Use Case |
|----------------|------|---------|----------|
| Levels | lin | Raw value | Actual amounts |
| Change | chg | x_t - x_{t-1} | Period-to-period change |
| Change from Year Ago | ch1 | x_t - x_{t-n} | Annual change |
| Percent Change | pch | ((x_t/x_{t-1})-1)*100 | Growth rates |
| Percent Change from Year Ago | pc1 | ((x_t/x_{t-n})-1)*100 | Annual growth |
| Compounded Annual Rate | pca | (((x_t/x_{t-1})^(n))-1)*100 | Annualized growth |
| Continuously Compounded Rate | cch | (ln(x_t)-ln(x_{t-1}))*100 | Log returns |
| Continuously Compounded Annual | cca | (ln(x_t)-ln(x_{t-n}))*100 | Log annual returns |
| Natural Log | log | ln(x_t) | Statistical analysis |
### Aggregation Methods
When converting frequency:
| Method | Description | Best For |
|--------|-------------|----------|
| Average | Mean of period | Flow variables (rates, prices) |
| Sum | Total of period | Stock variables (production, sales) |
| End of Period | Last value | Levels, indices |
## Data Quality
### Revisions
Economic data undergoes revisions:
<Steps>
<Step title="Preliminary Release">
Initial estimate based on partial data
</Step>
<Step title="Revised Release">
Updated with more complete information
</Step>
<Step title="Final Release">
Comprehensive data, may come months later
</Step>
<Step title="Annual Revisions">
Methodological updates and rebasing
</Step>
</Steps>
### Vintage Data
FRED maintains historical snapshots:
```json
{
"realtime_start": "2024-01-05",
"realtime_end": "2024-01-05",
"observation_start": "2023-12-01",
"observation_end": "2023-12-01",
"vintage_dates": [
"2024-01-05",
"2023-12-08",
"2023-11-03"
]
}
```
This allows analysis of:
- Data as it was known at specific dates
- Magnitude of revisions
- Forecasting accuracy
### Missing Values
Series may have gaps:
- Discontinued series
- Weekends/holidays (daily data)
- Not-yet-released observations
- Suppressed values (privacy/reliability)
Represented as:
```json
{
"date": "2024-01-01",
"value": "."
}
```
## Search and Discovery
### Full-Text Search
Search across:
- Series titles
- Series descriptions
- Category names
- Tag names
- Release names
**Example:**
```
"unemployment" → Returns ~500 series
"unemployment rate seasonally adjusted" → ~50 series
"UNRATE" → Exact match
```
### Tag-Based Filtering
Combine multiple tags:
```
tags: ["monthly", "sa", "bls", "employment"]
```
### Category Browsing
Navigate hierarchy:
```
Root (0)
└─ Population, Employment & Labor Markets (10)
└─ Current Employment Statistics (11)
└─ [~500 series]
```
## Common Series
### Key Economic Indicators
<AccordionGroup>
<Accordion title="Labor Market (Monthly)">
- **UNRATE**: Unemployment Rate (SA)
- **PAYEMS**: Total Nonfarm Payrolls (SA)
- **CIVPART**: Labor Force Participation Rate (SA)
- **U6RATE**: Total Unemployed + Marginally Attached (SA)
</Accordion>
<Accordion title="GDP & Production (Quarterly)">
- **GDP**: Gross Domestic Product (SAAR)
- **GDPC1**: Real GDP (SAAR)
- **INDPRO**: Industrial Production Index (SA)
- **TCU**: Capacity Utilization (SA)
</Accordion>
<Accordion title="Inflation (Monthly)">
- **CPIAUCSL**: CPI All Items (SA)
- **CPILFESL**: CPI Less Food & Energy (SA)
- **PCEPI**: PCE Price Index (SA)
- **PCEPILFE**: Core PCE Price Index (SA)
</Accordion>
<Accordion title="Interest Rates (Daily)">
- **DFF**: Federal Funds Effective Rate
- **DGS10**: 10-Year Treasury Constant Maturity
- **DGS2**: 2-Year Treasury Constant Maturity
- **T10Y2Y**: 10-Year minus 2-Year Treasury Spread
</Accordion>
</AccordionGroup>
## API Response Format
### Series Metadata
```json
{
"seriess": [{
"id": "GDP",
"realtime_start": "2024-10-01",
"realtime_end": "2024-10-01",
"title": "Gross Domestic Product",
"observation_start": "1947-01-01",
"observation_end": "2024-04-01",
"frequency": "Quarterly",
"frequency_short": "Q",
"units": "Billions of Dollars",
"units_short": "Bil. of $",
"seasonal_adjustment": "Seasonally Adjusted Annual Rate",
"seasonal_adjustment_short": "SAAR",
"last_updated": "2024-09-26 07:46:02-05",
"popularity": 92,
"notes": "BEA Account Code: A191RC..."
}]
}
```
### Observations Data
```json
{
"realtime_start": "2024-10-01",
"realtime_end": "2024-10-01",
"observation_start": "2020-01-01",
"observation_end": "2024-04-01",
"units": "lin",
"output_type": 1,
"file_type": "json",
"order_by": "observation_date",
"sort_order": "asc",
"count": 18,
"offset": 0,
"limit": 100000,
"observations": [...]
}
```
## Next Steps
<CardGroup cols={2}>
<Card
title="API Tools"
icon="wrench"
href="/api-reference/overview"
>
Use data retrieval tools
</Card>
<Card
title="Examples"
icon="code"
href="/examples/basic-usage"
>
See practical examples
</Card>
<Card
title="Common Series"
icon="chart-line"
href="/resources/common-series"
>
Popular indicators
</Card>
<Card
title="Transformations"
icon="calculator"
href="/resources/data-transformations"
>
Data transformation guide
</Card>
</CardGroup>
