Gera Local Wage Premium US — Methodology

1. What the GLWP-US measures

The Gera Local Wage Premium US (GLWP-US) is a county-level index showing how the average weekly wage in a US county compares to the national average, computed from BLS QCEW 2023 establishment data. It is designed to answer: “Is this county a high-wage or low-wage area, relative to the US as a whole?”

• Wage component: annual average weekly wage across all industries and all ownership types (private + government) per county.
• Employment concentration (LQ): for context, GeraJobs also shows the top 5 NAICS sectors by employment Location Quotient (LQ) for private-sector workers — identifying which industries are over-represented in the county relative to the US.

The GLWP-US is distinct from the Gera US Pay Premium Index (GUPPI), which is built from BLS OEWS and measures state-level wage premiums by occupation. QCEW is coarser on occupation but covers 3,100+ counties (vs 50 states in OEWS) and includes government workers.

2. Source data

All figures are sourced from the BLS Quarterly Census of Employment and Wages (QCEW), 2023 Annual Single File — a US public-domain, key-free bulk download:

The QCEW covers UI-covered employment, which is more than 95% of total US wage-and-salary employment. Suppressed rows (disclosure_code=N) are excluded; no cell is imputed or fabricated. No API key or registration is required — the annual singlefile ZIP is freely downloadable.

3. Formula

Step 1 — Extract county and US wage baselines

Step 2 — Compute GLWP-US

Rounded to 1 decimal place. US = 100 by construction (the US row itself returns exactly 100.0).

Step 3 — Employment LQ (sector specialisation)

BLS computes the LQ as: (county_sector_emp / county_total_emp) / (US_sector_emp / US_total_emp). GeraJobs reads this directly from the singlefile field lq_annual_avg_emplvl at agglvl=74 (private sector by NAICS sector). No re-computation is performed.

Observed range (2023, 3,141 counties)

Highest: Santa Clara County, California — GLWP-US 241.3 ($3359/wk).
Lowest: Worth County, Missouri — GLWP-US 41.0 ($571/wk).

4. Reproducibility

1. Download 2023_annual_singlefile.zip from data.bls.gov/cew/data/files/ (no key or registration required).
2. Extract and open the CSV. Filter to agglvl_code=10, area_fips="US000", industry_code=10, own_code=0→ read annual_avg_wkly_wage= $1,392 (this is the US GLWP-US denominator).
3. For each county row with agglvl_code=70, own_code=0, industry_code=10, disclosure_code ≠ N: compute (annual_avg_wkly_wage / 1392) × 100→ GLWP-US.
4. Cross-check: the US row (area_fips=US000, agglvl_code=10) should return GLWP-US = 100.0 exactly. Any county with the exact national average wage also returns 100.0 by definition.
5. For sector LQs: filter to agglvl_code=74, own_code=5. The lq_annual_avg_emplvlfield is the BLS pre-computed LQ — no further computation needed.

The computation is deterministic — no random seeds, no ML, no interpolation. Any third party can reproduce every number to one decimal place from the same BLS source file.

5. Limitations

• All-industry average: The GLWP-US is an average across all sectors. A county with a dominant high-wage industry (e.g. finance, tech) will score high even if most local residents earn less. The sector LQs provide context on the source of the premium.
• Not cost-of-living adjusted: A GLWP-US of 200 in San Francisco does not mean workers in San Francisco are twice as wealthy as the US average — cost of living is much higher. See the Gera US Real Pay Index for cost-adjusted figures.
• Suppression: BLS suppresses rows for small counties where data could identify individual establishments. These rows havedisclosure_code=Nand are excluded. 3,141 counties passed the suppression threshold.
• UI coverage: QCEW covers UI-taxed employment (>95% of wage employment). Self-employed individuals and certain agricultural workers are not included.
• Sector LQ uses private sector only: agglvl=74, own_code=5 (private). Government workers' industry concentration is not included in the LQ breakdown (though their wages ARE included in the GLWP-US numerator via agglvl=70, own_code=0 which covers all ownership).
• Annual average: The QCEW annual single-file reports the average across all four quarters. Seasonal counties (ski resorts, tourist areas) may show lower averages than their peak-season wages suggest.

6. Licence

Source data: U.S. Bureau of Labor Statistics, Quarterly Census of Employment and Wages (QCEW), 2023 Annual Single File. BLS products are US federal government works and are in the public domain under 17 U.S.C. § 105 — no licence restrictions. usa.gov/government-works.

The Gera Local Wage Premium US (GLWP-US) index and methodology are published by GeraJobs (Gera Systems Ltd) and may be cited freely with attribution: “Gera Local Wage Premium US, GeraJobs (gerajobs.com/us-wage-premium/methodology), computed from BLS QCEW 2023 under US public domain.”