Worker Drug Use and Workplace Policies and Programs: Results from the 1994 and 1997 National Household Survey on Drug Abuse

APPENDIX A: STANDARD ERROR TABLES

As stated earlier, this report presents results of tests of statistical significance for comparisons of prevalence estimates. Differences were tested for statistical significance using Z tests. The Z test takes into account the sizes of the subsamples being compared and the degree of variation among sample members. Statistical significance refers to the probability that a difference as large as that observed would occur due to random error in the estimates if there were no difference in the prevalence rates in the groups being compared. Unless otherwise noted, differences discussed in the text were statistically significant at the .05 level or lower. That is, a sample difference equal to or larger than the observed sample difference is likely to occur fewer than 5 times in 100 by chance alone (.05 level). Analogous definitions apply to significance at the .10 and .01 levels.

Standard errors of the estimates are not presented in the main text of this report. However, this appendix contains standard errors for the estimates presented in this report. These standard errors were calculated using SUDAAN⁶. The reader may use these standard errors to perform additional hypothesis testing. The difference in prevalence rates may be determined using the standard difference in percentages test expressed as



where p₁ is the estimated percentage of the first subgroup (e.g., the estimated percentage of the 1994 population who reported drug or alcohol testing in the workplace), p₂ is the corresponding estimate of the second group (e.g., the 1997 population), SE(p₁) is the standard error of p₁, and SE(p₂) is the standard error of p₂. So, using our example, as shown in Table 5.1, 43.6 percent of the 1994 population reported drug or alcohol testing in the workplace and 48.5 percent of the 1997 population reported the same workplace characteristic. As shown in Table A5.1, the standard errors for these estimates are 1.1 and 1.2, respectively. Therefore, using the above equation it follows that Z = 3.01, which is greater than the critical value of 2.58. Therefore, the difference in the two percentages is significant at the .01 level.

The standard error tables are numbered to correspond with the detailed data tables. For example the standard errors for Table 1.1 are found in Table A1.1.

 

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1994-B, 1997.

 

Table A1.2 Trends in Percentage of Persons, Age 18-49, Reporting Drug Use, by Employment Status, STANDARD ERRORS, 1985-1997
Employment Status	Current Illicit Drug Use											Current Heavy Alcohol Use1
	1985	1988	1990	1991	1992	1993	1994	1995	1996	1997		1985	1988	1990	1991	1992	1993	1994	1995	1996	1997
Total	0.8	0.7	0.7	0.4	0.3	0.5	0.4	0.4	0.4	0.4		0.6	0.4	0.4	0.3	0.4	0.4	0.4	0.3	0.3	0.5
Full-time	1.0	0.8	0.7	0.4	0.4	0.5	0.5	0.5	0.5	0.5		9.7	0.7	0.5	0.4	0.4	0.5	0.5	0.4	0.4	0.6
Part-time	1.7	1.5	1.6	1.1	0.9	1.5	0.9	1.1	1.0	0.8		1.3	1.4	1.1	0.6	1.1	0.9	0.7	0.8	0.7	0.8
Unemployed	3.1	2.9	2.3	1.7	1.4	1.5	1.8	1.2	1.4	2.6		1.8	1.8	1.7	1.6	1.4	1.7	1.5	1.1	1.6	2.5

Employment Status	Past Year Illicit Drug Use
	1985	1988	1990	1991	1992	1993	1994	1995	1996	1997
Total	0.9	1.0	0.9	0.5	0.6	0.6	0.5	0.6	0.6	0.6
Full-time	1.1	1.1	1.1	0.6	0.7	0.7	0.6	0.6	0.7	0.7
Part-time	2.3	2.1	1.8	1.2	1.4	1.8	1.3	1.4	1.6	1.2
Unemployed	3.0	3.3	3.1	2.1	1.6	2.1	2.0	2.1	2.1	3.0

¹ Current heavy alcohol use is defined as drinking five or more drinks on the same occasion on each of at least five days in the previous 30 days.

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse: 1985-1997.  

 

Table A1.3 Percentage of 18-49 Year Olds Reporting Current Illicit Drug Use, by Type of Drug, STANDARD ERRORS, 1994 and 1997

² Hallucinogenic drugs include a number of illicit drugs such as LSD, Peyote, Mescaline, Psilocybin, PCP, and Ecstasy.

³ Inhalants are fumes or gases that are inhaled to produce intoxication. They include a number of substances such as glues, aerosols, butane, ether, amyl nitrite, nitrous oxide, and solvents.

^a Difference between estimate and 1994 estimate is statistically significant at the .05 level.

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1994B and 1997. 

 

 

Table A2.1 Percentage of Full-Time Workers, Age 18-49, Reporting Current Illicit Drug and Current Heavy Alcohol Use, by Demographic Characteristics, STANDARD ERRORS, 1994 and 1997

¹ Heavy alcohol use is defined as drinking five or more drinks on the same occasion on each of at least five days in the previous 30 days.

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1994-B, 1997.  

 

Table A2.2 Distribution of Full-Time Workers, Age 18-49, Reporting Current Illicit Drug and Current Heavy Alcohol Use, by Demographic Characteristics, STANDARD ERRORS, 1994 and 1997

¹ Heavy alcohol use is defined as drinking five or more drinks on the same occasion on each of at least five days in the previous 30 days.

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1994-B, 1997.

 

Table A2.3 Percentage of Illicit Drug and Heavy Alcohol Users Among Full-Time Workers, Age 18-49, by Establishment Size, STANDARD ERRORS, 1994 and 1997
Establishment Size	Illicit Drug Use			Heavy Alcohol Use1			Total Full-Time Workers
1994
Total	0.5			0.5			-
1-24 Employees	0.9			0.7			1.0
25-499 Employees	0.6			0.6			1.0
500+ Employees	0.8			1.2			0.7
1997
Total	0.5			0.6			-
1-24 Employees	1.0			0.9			1.3
25-499 Employees	0.7			1.1			1.2
500+ Employees	1.5			1.3			1.0

Note: Subtotals may not sum to totals due to rounding error. The estimated numbers in this table differ from the estimated numbers found in other tables due to missing values on the establishment size variable.

¹ Heavy alcohol use is defined as drinking five or more drinks on the same occasion on each of at least five days in the previous 30 days.

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1994-B, 1997.

 

Table A2.4 Percentage of Full-Time Workers, Age 18-49, Reporting Workplace Drug or Alcohol Testing, Current Illicit Drug Use, and Heavy Alcohol Use, by Occupation Categories, STANDARD ERRORS, 1994 and 1997
Occupation Category		Workplace Drug/Alcohol Testing				Current Illicit  Drug Use				Current Heavy Alcohol Use1
		1994	1997	Diff.2		1994	1997	Diff.2		1994	1997	Diff.2
Total		1.1	1.3	1.7		0.5	0.5	0.8		0.5	0.6	0.7
Executive, Administrative & Managerial		2.2	3.3	4.0		1.1	2.1	2.3		1.1	1.5	1.9
Professional Specialty		2.0	3.1	3.7		1.0	1.0	1.4		1.0	1.4	1.7
Technicians & Related Support		4.6	5.3	7.0		1.4	3.1	3.3		1.6	1.6	2.3
Sales		2.5	3.0	3.9		1.7	2.3	2.9		1.3	0.9	1.5
Administrative Support		2.4	2.6	3.5		1.0	0.6	1.2		0.7	1.3	1.5
Protective Service		5.5	3.4	6.5		1.6	1.6	2.3		3.0	2.3	3.8
Food Preparation, Waiters, Waitresses & Bartenders		2.5	3.2	4.1		2.1	3.8	4.4		2.3	3.1	3.9
Other Service		3.1	4.6	5.9		1.3	4.0	4.2		1.6	4.4	4.7
Precision Production & Repair		4.3	6.3	7.6		2.0	1.6	2.6		2.5	2.5	3.6
Construction		3.5	3.9	5.2		2.2	2.8	3.6		2.4	3.6	4.3
Extractive & Precision Production		4.2	6.1	7.4		1.9	1.6	2.5		2.6	2.0	3.3
Machine Operators & Inspectors		3.7	3.4	2.9		1.9	1.8	2.6		2.3	1.7	2.9
Transportation & Material Moving		3.0	4.5	5.4		1.5	3.1	3.4		2.6	2.7	3.8
Handlers, Helpers & Laborers		3.9	6.0	7.1		2.5	1.5	2.9		3.1	3.6	4.7

¹ Heavy alcohol use is defined as drinking five or more drinks on the same occasion on each of at least five days in the previous 30 days.

² Diff. refers to percentage difference between 1994 and 1997.

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1994-B and 1997.

 

Table A3.1 Percentage of Full-Time Workers, Age 18-49, Reporting Various Workplace Outcomes, by Current Illicit Drug and Heavy Alcohol Use, STANDARD ERRORS, 1994 and 1997
	Current Illicit Drug Use					Heavy Alcohol Use1
Workplace Outcome	Yes		No			Yes		No
	1994	1997	1994	1997		1994	1997	1994	1997
Worked for three or more employers in the past year	1.4	1.6	0.3	0.4		1.5	1.4	0.3	0.4
Missed two or more days of work in the past month due to illness or injury	1.8	3.1	0.5	0.6		1.4	3.2	0.5	0.6
Skipped one or more days of work in the past month	1.8	3.3	0.4	0.4		1.7	3.1	0.4	0.4
Voluntarily left an employer in the past year	2.1	3.2	0.6	0.8		2.2	3.2	0.6	0.8
Fired by an employer in the past year	1.3	0.7	0.2	1.2		1.5	0.4	0.2	0.2
Had a workplace accident in the past year	1.3	1.1	0.4	0.4		1.4	2.6	0.4	0.4

¹ Current heavy alcohol use is defined as drinking five or more drinks on the same occasion on each of at least five days in the previous 30 days.

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1994-B, 1997.
 

 

Table A4.1 Percentage of Full-Time Workers, Age 18-49, Reporting That Their Workplace Provides Information, Has a Written Policy, or Maintains an Employee Assistance Program (EAP) Concerning Drug or Alcohol Use, by Establishment Size, 1994, 1997 B STANDARD ERRORS
	Information About Drug and Alcohol Use			Written Policy About Drug and Alcohol Use			Employee Assistance Program
Establishment Size	1994	1997		1994	1997		1994	1997
Total	0.7	1.0		0.7	1.0		0.9	1.6
1-24 Employees	1.4	1.8		1.6	1.8		1.2	1.7
25-499 Employees	0.9	1.0		0.9	1.1		1.2	1.6
500+ Employees	0.9	1.6		1.1	1.7		1.5	2.8

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1994-B, 1997.

 

Table A4.2 Percentage of Full-Time Workers, Age 18-49, Reporting That Their Workplace Provides Information, Has a Written Policy, or Maintains an Employee Assistance Program (EAP) Concerning Drug or Alcohol Use, by Establishment Size and Current Illicit Drug Use, STANDARD ERRORS, 1994 and 1997
	Information About Drug and Alcohol Use			Written Policy About Drug and Alcohol Use			Employee Assistance Program
Establishment Size	Current Illicit Drug Use	No Current Illicit Drug Use		Current Illicit Drug Use	No Current Illicit Drug Use		Current Illicit Drug Use	No Current Illicit Drug Use
1994
Total	2.6	0.7		2.7	0.7		2.5	0.9
1-24 Employees	4.2	1.5		4.4	1.6		2.6	1.3
25-499 Employees	3.3	0.9		3.8	1.0		5.5	1.3
500+ Employees	2.6	1.0		2.3	1.2		3.7	1.5
1997
Total	3.7	1.0		3.6	1.0		4.1	1.6
1-24 Employees	5.5	1.8		5.1	1.8		6.0	1.7
25-499 Employees	4.2	0.9		4.2	1.1		5.6	1.6
500+ Employees	3.5	1.7		4.4	1.8		8.4	2.9

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1994-B, 1997.

 

Table A4.3 Percentage of Full-Time Workers, Age 18-49, Reporting That Their Workplace Provides Information, Has a Written Policy, or Maintains an Employee Assistance Program (EAP) Concerning Drug or Alcohol Use, by Establishment Size and Current Heavy Alcohol Use, 1994, 1997 B Standard Errors
	Information About Drug and Alcohol Use			Written Policy About Drug and Alcohol Use			Employee Assistance Program
Establishment Size	Current Heavy Alcohol Use	No Current Heavy Alcohol Use		Current Heavy Alcohol Use	No Current Heavy Alcohol Use		Current Heavy Alcohol Use	No Current Heavy Alcohol Use
1994
Total	2.2	0.8		2.4	0.8		3.1	0.9
1-24 Employees	3.7	1.6		3.7	1.7		2.6	1.3
25-499 Employees	3.5	0.9		4.0	0.9		4.3	1.2
500+ Employees	1.3	1.0		0.9	1.2		4.9	1.6
1997
Total	3.1	1.0		3.3	1.0		3.7	1.6
1-24 Employees	5.0	1.8		4.7	1.9		4.1	1.7
25-499 Employees	3.3	1.0		3.5	1.2		6.7	1.8
500+ Employees	2.0	1.7		2.1	1.8		8.4	2.9

 

Table A4.4 Percentage of Full-Time Workers, Age 18-49, Reporting That Their Workplace Provides Information, Has a Written Policy, or Maintains an Employee Assistance Program (EAP) Concerning Drug or Alcohol Use, by Occupation Categories, STANDARD ERRORS, 1994 and 1997

 

Table A5.1 Percentage of Full-Time Workers, Age 18 - 49, Reporting Workplace Drug Testing Programs, by Establishment Size, STANDARD ERRORS, 1994 and 1997

Note: The denominator refers to all those full-time workers, age 18-49, in the sample.

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1994-B, 1997.  

Table A5.3 Percentage of Full-Time Workers, Age 18-49, Reporting Workplace Drug Testing Programs, by Establishment Size and Current Illicit Drug Use, STANDARD ERRORS, 1994 and 1997

 

Table A5.4 Percentage of Full-Time Workers, Age 18 - 49, Reporting That They Would be LESS LIKELY to Work for an Employer Who Tests for Drug Use in Various Circumstances, by Establishment Size and Current Illicit Drug Use, STANDARD ERRORS, 1994 and 1997

 

Table A5.5 Percentage of Full-Time Workers, Age 18-49, Reporting That They Would Be LESS LIKELY to Work for an Employer Who Tests for Drug Use in Various Circumstances, by Occupation Categories, STANDARD ERRORS, 1994, 1997 and the Difference

Source: Office of Applied Studies, SAMHSA, National Household Survey on Drug Abuse, 1994-B, 1997.

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