economy_industrial_concentration_county_year
HHI and predominant sector from NAICS-2 private-sector employment shares (E2). Tier A. Powers scorecard concentration metrics.
overview
3,221 counties. QCEW NAICS-2 private sector coverage.
current vintage — 2024
history — NAICS-based: 2001-present; SIC-based pre-2001
source & licensing
fields
| name | type | definition |
|---|---|---|
| country_id | string | ISO alpha-2 country code (always 'US' for domestic tables). |
| county_idkey | string | 5-character FIPS code identifying the county.Joins dim.counties on county_id. |
| economic_concentration_hhi | float64 · index (0–10000) | Herfindahl-Hirschman Index (HHI) for the county's industry mix, computed as the sum of squared employment (or establishment) shares across all sectors, scaled to 0–10000. Higher values indicate greater concentration of economic activity in fewer industries. |
| predominant_sector | string | NAICS sector name or code representing the largest share of the county's economic activity in a given year. |
| predominant_sector_share | float64 · share (0–1) | Fraction of total county economic activity (e.g. employment or establishments) accounted for by the predominant sector. Higher values indicate greater dependence on a single industry. |
| runner_up_sector | string | NAICS sector name or code representing the second-largest share of the county's economic activity in a given year. |
| runner_up_sector_share | float64 · share (0–1) | Fraction of total county economic activity accounted for by the runner-up sector, i.e. the second-largest industry behind the predominant sector. |
| state_id | string | 2-character FIPS code identifying the state.Joins dim.states on state_id. |
| yearkey | int64 | Reference year of the observation. |
joins
how to use this table
HHI = SUM((employment_share_naics2_i)^2) over private NAICS-2 supersectors. predominant_sector = NAICS-2 with largest share. predominant_sector_share = max share. Government own_code='1','2','3' excluded.
Cross-NAICS-revision comparison (NAICS 2002, 2007, 2012, 2017, 2022 introduce small reclassifications); narrow industry concentration (use NAICS-4 or NAICS-6, not loaded here).
HHI computed at NAICS-2 only; misses concentration in narrow industries. Suppression in small cells biases HHI downward.