Wage discrimination against immigrants: measurement with firm-level productivity data

Table 6 Firm-level productivity equation

Log av. hourly value added	OLS	OLS	OLS	OLS	Fixed effects	GMM-IV
Log av. hourly value added	(1)	(2)	(3)	(4)	(5)	(6)
Share of non-EU workers^a	−0.38*** (0.04)	−0.12*** (0.04)	−0.12*** (0.04)	−0.08** (0.04)	−0.02 (0.04)	−0.00 (0.15)
Share of women	–	−0.20*** (0.03)	−0.22*** (0.03)	−0.12*** (0.02)	0.02 (0.04)	−0.27** (0.11)
Year dummies	Yes	Yes	Yes	Yes	Yes	Yes
Individual and job characteristics^b	No	Yes	Yes	Yes	Yes	Yes
Sectors and regions^c	No	No	Yes	Yes	Yes	Yes
Firm characteristics^d	No	No	No	Yes	Yes	Yes
Observations	23,712	23,712	23,712	23,712	23,712	8333
Adjusted R ²	0.01	0.19	0.20	0.30		0.00
Within R ²					0.02
Between R ²					0.11
Underidentification test^e						0.00
Weak identification test^f						68.4
Overidentification test^g						0.82
Endogeneity test^h						0.98

Data source: SES-SBS 1999–2010; HAC standard errors in parentheses
***, ** significant at 1, 5 and 10 % levels, respectively
^aOmitted reference: share of EU workers
^bIndividual and job characteristics include share of workers younger than 40 years, share of 8 occupational groups (reference: service occupations); 3 educational levels (reference: ISCED 1–2); share of fixed-term contracts; share of workers with more than 5 years of tenure
^cSector and regional controls include 9 sectors (reference: manufacturing) and 3 regions (reference: Flanders)
^dFirm controls include the logarithm of firm size, logarithm of capital and a dummy for firm-level collective bargaining. All regressions include year dummies
^eUnderidentifcation test reports p value of Kleibergen-Paap rk LM statistic
^fWeak identification test reports Kleibergen-Paap rk Wald F statistic
^gOveridentification test reports p value of Hansen J statistic
^hEndogeneity test shows probability that endogenous regressors can actually be treated as exogenous