Table 9. Effect of Union Status on Persons Affected Penalty Points per S&S Violation
10 Most Common Violation Types
(Full Version: All Covariates)
Specification	Baseline (Hours Worked)	Employees	Tonnage
Union	0.182**	0.274**	0.240**	0.360***	0.114	0.219**
	(0.09)	(0.11)	(0.10)	(0.12)	(0.09)	(0.11)
Union X Mine Size	-0.028	-0.030	-0.056*	-0.065**	-0.007	-0.044
	(0.02)	(0.02)	(0.03)	(0.03)	(0.07)	(0.08)
Mine Size	0.010	-0.016	0.018	-0.003	-0.036	-0.126
	(0.03)	(0.03)	(0.03)	(0.04)	(0.07)	(0.08)
Log of Controller Size	-0.038***	-0.045***	-0.040***	-0.051***	-0.028**	-0.035**
	(0.01)	(0.02)	(0.01)	(0.02)	(0.01)	(0.01)
Lost-Day Injuries in Prev. Year	-0.008**	-0.007**	-0.008**	-0.007**	-0.008***	-0.008***
	(0.00)	(0.00)	(0.00)	(0.00)	(0.00)	(0.00)
Penalty Pts. in Prev. Year	0.003	0.004	0.003	0.003	0.004	0.003
	(0.00)	(0.00)	(0.00)	(0.00)	(0.00)	(0.00)
Mine Age	0.002	-0.001	0.003	-0.000	0.002	-0.001
	(0.00)	(0.00)	(0.00)	(0.00)	(0.00)	(0.00)
Productivity	-0.006	-0.009*	-0.006	-0.009*	-0.003	-0.001
	(0.00)	(0.01)	(0.00)	(0.01)	(0.01)	(0.01)
NIOSH Longwall Dummy	0.218**		0.223**		0.235**
	(0.09)		(0.09)		(0.09)
Number of Coal Beds		0.109		0.119		0.101
		(0.13)		(0.13)		(0.13)
Avg. Coal Bed Thickness (yds.)		-0.071		-0.077		-0.077
		(0.05)		(0.05)		(0.05)
Subsidiary Indicator		-0.005		0.001		-0.001
		(0.06)		(0.06)		(0.06)
Pct. Captive Production		-0.084		-0.093		-0.097
		(0.09)		(0.10)		(0.10)
Recoverable Reserves		-0.000		-0.000		-0.000
		(0.00)		(0.00)		(0.00)
Pct. Continuous Mining Method		-0.001		-0.002		-0.002
		(0.00)		(0.00)		(0.00)
Pct. Conventional Mining Method		-0.001		-0.001		-0.001
		(0.00)		(0.00)		(0.00)
Pct. Longwall Mining Method		0.004		0.003		0.003
		(0.00)		(0.00)		(0.00)
Pct. Shortwall Mining Method		-0.011***		-0.011***		-0.012***
		(0.00)		(0.00)		(0.00)
Constant	1.838***	1.699***	1.648***	1.693***	1.617***	1.651***
	(0.21)	(0.35)	(0.20)	(0.36)	(0.20)	(0.37)
Subunit Dummies	Yes	Yes	Yes	Yes	Yes	Yes
Quarter Dummies	Yes	Yes	Yes	Yes	Yes	Yes
District Dummies	Yes	Yes	Yes	Yes	Yes	Yes
Violation Type Dummies	Yes	Yes	Yes	Yes	Yes	Yes
Observations	106,483	83,968	104,030	82,081	104,030	82,081
# of Union Mines / # of Total Mines	226 / 1,547	150 / 1,134	225 / 1,540	150 / 1,129	225 / 1,540	150 / 1,129
R2	0.12	0.12	0.12	0.12	0.12	0.12
Regression Date/Time	12/2/11 22:28	12/2/11 22:28	12/2/11 22:28	12/2/11 22:29	12/2/11 22:29	12/2/11 22:29

Table 9. Effect of Union Status on Persons Affected Penalty Points per S&S Violation

10 Most Common Violation Types

(Full Version: All Covariates)

Specification

Baseline (Hours Worked)

Employees

Tonnage

Model

Public Fields Only

Confidential Fields

Public Fields Only

Confidential Fields

Public Fields Only

Confidential Fields

Mine/Controller Size Units:

100 Quarterly FTEs

100 Employees

Millions of Tons

Union

0.182**

0.274**

0.240**

0.360***

0.114

0.219**

(0.09)

(0.11)

(0.10)

(0.12)

(0.09)

(0.11)

Union X Mine Size

-0.028

-0.030

-0.056*

-0.065**

-0.007

-0.044

(0.02)

(0.03)

(0.07)

(0.08)

Mine Size

0.010

-0.016

0.018

-0.003

-0.036

-0.126

(0.03)

(0.04)

(0.07)

(0.08)

Log of Controller Size

-0.038***

-0.045***

-0.040***

-0.051***

-0.028**

-0.035**

(0.01)

(0.02)

(0.01)

(0.02)

(0.01)

Lost-Day Injuries in Prev. Year

-0.008**

-0.007**

-0.008**

-0.007**

-0.008***

(0.00)

Penalty Pts. in Prev. Year

0.003

0.004

0.003

0.004

0.003

(0.00)

Mine Age

0.002

-0.001

0.003

-0.000

0.002

-0.001

(0.00)

Productivity

-0.006

-0.009*

-0.006

-0.009*

-0.003

-0.001

(0.00)

(0.01)

(0.00)

(0.01)

NIOSH Longwall Dummy

0.218**

0.223**

0.235**

(0.09)

Number of Coal Beds

0.109

0.119

0.101

(0.13)

Avg. Coal Bed Thickness (yds.)

-0.071

-0.077

(0.05)

Subsidiary Indicator

-0.005

0.001

-0.001

(0.06)

Pct. Captive Production

-0.084

-0.093

-0.097

(0.09)

(0.10)

Recoverable Reserves

-0.000

(0.00)

Pct. Continuous Mining Method

-0.001

-0.002

(0.00)

Pct. Conventional Mining Method

-0.001

(0.00)

Pct. Longwall Mining Method

0.004

0.003

(0.00)

Pct. Shortwall Mining Method

-0.011***

-0.012***

(0.00)

Constant

1.838***

1.699***

1.648***

1.693***

1.617***

1.651***

(0.21)

(0.35)

(0.20)

(0.36)

(0.20)

(0.37)

Subunit Dummies

Yes

Quarter Dummies

Yes

District Dummies

Yes

Violation Type Dummies

Yes

Observations

106,483

83,968

104,030

82,081

104,030

82,081

# of Union Mines / # of Total Mines

226 / 1,547

150 / 1,134

225 / 1,540

150 / 1,129

225 / 1,540

150 / 1,129

0.12

Regression Date/Time

12/2/11 22:28

12/2/11 22:29

Definitions: Significance Levels: *** 1%, ** 5%, * 10%. FTE is defined as 2,000 man-hours.

Models: All models are ordinary least squares regressions; standard errors (shown in parentheses) are clustered at the mine level. The unit of analysis for all models is the s&s violation

10 most common violation types

Sample: public sample is: (sig_or_sub==1) (ten_most_common_violation==1) (violator_contractor==0) (underground_mine==1) (coal_dummy==1) (bituminous==1) (active==1) (first_qtr_of_production==0) inrange(year, 1995, 2009). private sample is: (sig_or_sub==1) (ten_most_common_violation==1) (violator_contractor==0) (underground_mine==1) (coal_dummy==1) (bituminous==1) (active==1) (first_qtr_of_production==0) inrange(year, 1998, 2009).

Independent Variables: All models include the following regressors: union dummy, union-size interaction term, mine size measure (defined as specified in column headers), logged controller size measure (defined as specified in column headers), mine age, productivity, number of lost-work injuries (in hundreds) in the previous four quarters, total penalty points (in thousands) in the previous four quarters, a constant term, dummies indicating presence of each type of mine subunit, quarter dummies, district dummies, and dummies for each violation type (i.e., section of CFR deemed to have been violated. In addition: "Public Fields Only" models include the NIOSH longwall dummy; and "Confidential Fields" models include number of coal beds, mean coal bed thickness (in yards), subsidiary indicator, captive production as a percentage of total production, recoverable coal reserves, and mining method percentages.

Dependent Variable: the number of penalty points assigned due to the number of persons that could be affected per S&S violation (limited to ten most common violation types).