> ## Documentation Index
> Fetch the complete documentation index at: https://docs.axiomancer.io/llms.txt
> Use this file to discover all available pages before exploring further.

# LEHD Commuter Flows schema

> Full field reference for the LEHD Commuter Flows dataset — 454K origin-destination pairs from Census LODES v8 normalized to H3 cells with accessibility indices.

The LEHD Commuter Flows dataset contains \~454K origin-destination pairs derived from Census Bureau LODES v8 (Longitudinal Employer-Household Dynamics). Each pair represents a commute flow between two H3 resolution-8 cells, enriched with income breakdowns, NAICS sector counts, and Codex-computed accessibility indices.

Every record inherits the full [APRS envelope](/codex/normalization-standard) (`record_id`, `chunk_id`, bitemporal fields, `confidence_score`, `provenance`) and carries the [join keys](/codex/join-keys) documented below.

## Dataset-specific fields

### Flow identifiers

| Field                    | Type   | Nullable | Description                                                                                      |
| ------------------------ | ------ | :------: | ------------------------------------------------------------------------------------------------ |
| `origin_h3`              | string |    no    | H3 resolution-8 cell of the workplace (derived from LODES `w_geocode`).                          |
| `destination_h3`         | string |    no    | H3 resolution-8 cell of the residence (derived from LODES `h_geocode`).                          |
| `origin_block_fips`      | string |    no    | Census block FIPS code (15-character) for the workplace. Retained as a Census-native identifier. |
| `destination_block_fips` | string |    no    | Census block FIPS code for the residence.                                                        |
| `metro_slug`             | string |    yes   | Metro area identifier (derived from metro FIPS).                                                 |

### Worker counts

| Field                  | Type    | Nullable | Description                                                     |
| ---------------------- | ------- | :------: | --------------------------------------------------------------- |
| `worker_count`         | integer |    no    | Total number of jobs (LODES `S000`).                            |
| `worker_count_lt30k`   | integer |    no    | Jobs with earnings \< \$1,250/month (LODES `SE01`).             |
| `worker_count_30to60k` | integer |    no    | Jobs with earnings $1,251–$3,333/month (LODES `SE02`).          |
| `worker_count_gt60k`   | integer |    no    | Jobs with earnings > \$3,333/month (LODES `SE03`).              |
| `income_band`          | enum    |    no    | Codex-derived dominant income band: `low`, `mid`, or `high`.    |
| `job_sector_naics`     | string  |    yes   | NAICS sector code with aggregated counts (LODES `SI01`–`SI03`). |

### Codex enrichments

| Field                 | Type         | Nullable | Description                                                                                                                   |
| --------------------- | ------------ | :------: | ----------------------------------------------------------------------------------------------------------------------------- |
| `accessibility_index` | float \[0,1] |    no    | Codex-computed accessibility score per origin-destination H3 pair. Higher values indicate better transit and commute options. |
| `distance_km`         | float        |    no    | Centroid-to-centroid distance in kilometers between origin and destination H3 cells.                                          |
| `h3_neighbor_rank`    | integer      |    no    | k-ring distance from origin to destination (0 = same cell, 1 = immediate neighbor, etc.).                                     |
| `lehd_year`           | integer      |    no    | Reference year for the LODES data (e.g. `2023`).                                                                              |

## Income bands

The `income_band` field is derived from the LODES earnings breakdown:

| Band   | Criterion                                     |
| ------ | --------------------------------------------- |
| `low`  | Plurality of workers earn \< \$1,250/month    |
| `mid`  | Plurality of workers earn $1,251–$3,333/month |
| `high` | Plurality of workers earn > \$3,333/month     |

## Accessibility index

The `accessibility_index` is a Codex-computed score that factors in transit coverage, commute distance, and commute volume between the origin and destination cells. It is useful for identifying well-connected corridors versus underserved commute routes.

<Note>
  Census LODES data includes noise infusion to protect respondent privacy. Codex preserves this noise as-is — small counts (under \~10 workers) may not reflect exact flows.
</Note>

## Join keys

| Key                      | Presence | Notes                                                                    |
| ------------------------ | :------: | ------------------------------------------------------------------------ |
| `record_id`              |  always  | APRS URN                                                                 |
| `chunk_id`               |  always  | Deterministic from `record_id`                                           |
| `origin_h3`              |  always  | Join with Urban Signal Grid, POI Intelligence, or any H3-indexed dataset |
| `destination_h3`         |  always  | Same as above                                                            |
| `origin_block_fips`      |  always  | Census-native identifier for block-level joins                           |
| `destination_block_fips` |  always  | Same as above                                                            |
| `metro_slug`             |   often  | Metro area identifier                                                    |

## Example query

Find the highest-volume commute corridors into a downtown cell:

```sql theme={null}
SELECT
  origin_h3,
  destination_h3,
  worker_count,
  income_band,
  accessibility_index,
  distance_km
FROM read_parquet('lehd-commuter-flows-2026-04.parquet')
WHERE destination_h3 = '88283082b9fffff'
  AND worker_count >= 50
ORDER BY worker_count DESC
LIMIT 20;
```

## Known limitations

* LODES data lags by 2–3 years. The `lehd_year` field indicates the reference year — it does not reflect current conditions.
* Census noise infusion means small cell-pair flows (under \~10 workers) carry significant uncertainty.
* Block-level granularity is collapsed to H3 resolution 8. Multiple Census blocks may map to the same H3 cell.
* `metro_slug` is null for flows in rural areas outside defined metro boundaries.