Table 4

Local Employer Concentration and Wages Controlling for Labor Value Added

Dep. Var.: Log Avg. Wages
CountyCZ
SIC3
(1)
SIC3
(2)
SIC4
(3)
SIC4
(4)
SIC3
(5)
SIC3
(6)
SIC4
(7)
SIC4
(8)
log(HHI, ind–local–year)-0.010-0.009-0.013-0.011-0.010-0.010-0.012-0.012
-3.28-3.24-4.34-4.25-3.26-3.24-4.02-3.83
log(emp, ind–local–year)0.0320.0320.0300.0310.0320.0320.0300.031
36.1033.9239.4438.1533.1330.4635.5233.17
log(labor productivity)0.0620.0600.0570.0560.0610.0590.0570.054
36.1830.6931.6926.9430.2425.9125.8222.74
log(labor VA)0.0110.0100.0100.0090.0110.0100.0110.009
15.5912.6915.2611.3816.1713.0115.2511.72
log(plants per segment)-0.007-0.008-0.006-0.007-0.006-0.007-0.005-0.006
-5.12-5.46-4.75-4.83-4.33-4.64-4.33-4.10
log(plants per firm)-0.007-0.006-0.008-0.007
-4.50-4.38-4.58-4.41
Plant age (/100)0.2650.2740.2560.2630.2840.2910.2730.280
30.4330.9829.8429.5830.0031.3728.4528.60
Year fixed effectsYYYY
Industry fixed effectsYYYY
Industry–year fixed effectsYYYY
Firm fixed effectsYYYY
Firm-year fixed effectsYYYY
Observations946,000946,000946,000946,000946,000946,000946,00094,6000
R20.57150.65520.58500.67300.57200.65590.58640.6743
  • Notes: This table examines the effects of employer concentration in a local labor market on the wages of plants including an additional control for labor productivity—valued added (total value of shipments + net increase in inventories of finished goods and works in progress—material and energy costs) scaled by labor hours. The dependent variable is the log of average wages per worker as defined in Table 1. log(HHI) and log(employment) are lagged by one year. Columns 1–4 (Columns 5–8) present estimates using counties (CZs) to define local labor markets. Columns 1–2 and 5–6 (Columns 3–4 and 7–8) present estimates using three- and four-digit SIC industries to compute HHI, log (employment), and log(plants per segment). The t-statistics based on standard errors adjusted for sample clustering at the county or CZ level are reported below the coefficient estimates. The numbers of observations are rounded to the nearest thousand to follow the U.S. Census Bureau’s disclosure rules.