An Analysis of Worker Drug Use and Workplace Policies and Programs

7.2 Limitations

As noted in Chapter 1, there are several limitations to the data and the analyses presented in this report that should considered when examining the results. First, since NHSDA respondents are not followed over time (each interview is conducted only one time per person), we cannot assess the direction of influence between current illicit drug or heavy alcohol use and workplace characteristics or outcomes. That is, it is not clear whether work conditions in certain occupations, establishment sizes, or among certain demographic groups are influencing drug use, or whether workers who use illicit drugs or engage in heavy alcohol use tend to gravitate toward certain types of occupations or establishments. For example, as suggested in Chapter 4, construction workers are overwhelmingly male and food and beverage workers tend to be young (see Hoffmann et al., 1996). Considering that both gender and age are strongly associated with current illicit drug use and heavy alcohol use among full-time workers (see Chapter 2), it may not be surprising that relatively high rates of current illicit drug use or heavy alcohol use are found among these two occupational groups. Similarly, the association between current illicit drug use or heavy alcohol use and certain work-related outcomes such as changing jobs or being fired could be explained in a number of ways: Current illicit drug use or heavy alcohol use might lead to these outcomes, or frequent job changes or being fired might affect subsequent drug use (see Mensch and Kandel, 1988).

Second, a more consequential limitation of the analysis involves the fact that there are important associations among demographic characteristics, occupational groups, and establishment size that are often masked when one looks at simple associations between these variables and worker drug or alcohol use. These variables may confound the association between any particular variable and drug or alcohol use. A good example of this potential drawback of the analysis involves the association between establishment size and current illicit drug use. If, on average, smaller establishments tend to employ younger workers or male workers, or to be in the construction and food service industries, then this might partly explain the association between establishment size and current illicit drug use. In order to determine whether the association between establishment size and current illicit drug use is confounded by other factors, one would have to control statistically for these other factors. However, there may be other factors not measured in the NHSDA questionnaire that also may confound any association between illicit drug or heavy alcohol use and workplace characteristics.

Another example of this potential problem involves the association between current illicit drug use or heavy alcohol use and work-related outcomes such as being fired from a job. In the absence of controls for other factors such as gender, age, other demographic characteristics, or certain types of behaviors (e.g., poor work habits) that might be associated with these outcomes, the precise association between current illicit drug use or heavy alcohol use and work-related outcomes is uncertain.

Third, since NHSDA data are based upon individual reports, there is likely to be a certain amount of error in the estimated prevalence of workplace policies and programs designed to address worker drug and alcohol use. Workers may not be fully aware of the nuances of policies or programs in their workplace. For example, some workers might be uncertain whether their workplace has written policies about employee drug use or maintains a post-accident drug testing program. Moreover, the data presented in Chapters 5 and 6 do notindicate the percentage of companies, employers, or establishments that provided information, had written policies, provided access to EAPs, or had drug testing programs; they only estimate the percentage of full-time workers who said that their workplace had these policies or programs. A national survey of companies or establishments would be needed to estimate the number or percentage of employers who had policies and programs aimed at employee drug and alcohol use (see, for example, Bureau of Labor Statistics, 1989; Hayghe, 1991; Hartwell et al., 1996).

Finally, the data used in this report do not indicate the circumstances or timing of current illicit drug use or heavy alcohol use. That is, the survey questions used to obtain these data ask about any illicit drug use or any heavy alcohol use in the past 30 days. While this is a good proxy for current use, there is no distinction made as to time-of-day or time-of-week of use (i.e., did it occur before, during, or after regular work hours?). Although current illicit drug users reported more work-related problems (see Chapter 1), the findings of this report cannot be used to make specific statements about on-the-job or off-duty drug or alcohol use.

This page was last updated on June 03, 2008.

SAMHSA, an agency in the Department of Health and Human Services, is the Federal Government's lead agency for improving the quality and availability of substance abuse prevention, addiction treatment, and mental health services in the United States.