The 1998 National Drug Strategy Household Survey
The 1998 National Drug Strategy Household Survey was the sixth
in a series which commenced in 1985. The Australian Institute of
Health and Welfare was commissioned in October 1997 by the
Commonwealth Department of Health and Family Services to manage the
survey. The Institute was assisted in this task by a Departmental
Policy Reference Group and a Technical Advisory Committee which
comprised members from the Australian Institute of Aboriginal and
Torres Strait Islander Studies, the Australian Bureau of Criminal
Intelligence, the National Drug and Alcohol Research Centre, the
Australian National University's Research School of Social
Sciences, and the Department's Research and Marketing Group.
Between June and September 1998 over 10,000 Australians aged 14
years or older selected from a geographic stratified random sample
of 8,357 private dwellings, completed the survey. Note that this
did not include institutionalised or homeless people. Persons aged
14 or 15 years participated with the consent of a parent or
guardian. The survey instrument comprised items on licit and
illicit drug-related awareness, knowledge, attitudes and
behaviours. Approximately 40% of the sample completed the survey
through personal interviews and a self-completion booklet for the
more sensitive issues. The balance of the sample self-completed the
entire questionnaire. The response rate achieved across the whole
sample was 56%.
Data presented in this release are based on estimates derived
from responses weighted to the total Australian population aged 14
years and over. Comparative data for 1995 were drawn from the
National Drug Strategy Household Survey of that year.
Because the results are based on survey responses, they are
subject to sampling variability. As an example, the number of 14-19
year old persons recently using marijuana/cannabis is shown as
547,000. Strictly speaking, we can only be 95% certain that the
value is in the range 499,000 to 595,000. The size of the range
varies with the magnitude of the estimate, the size of the
population for the which the estimate is made, and the degree of
certainty we want to attach to the range. Caution is therefore
recommended in interpreting low prevalence results: in general,
prevalence estimates below 1% are not statistically robust because
the margin of error is very large.
Drug-related mortality and morbidity
Estimates of drug-related deaths and hospital separations are
based on the application of aetiological fractions to data
contained in the Institute's National Mortality Database and
National Hospital Morbidity Database.
The aetiological fraction, which is also known as the
attributable proportion or attributable risk, is a form of indirect
quantification of drug-caused morbidity and mortality. Indirect
methods involve the estimation of a probability measure of the
likelihood of drug causation which is then applied to the total
numbers of deaths, illnesses or injuries
due to a specific cause. The distinguishing characteristic of
indirect methods is that individual drug caused cases are not
identified. For example, if the probability that a case of low
birthweight is caused by illicit drug use is .32 (that is a 32%
likelihood), then the product of this aetiologic fraction and the
total number of low birthweight babies in a population results in
an estimate of all low birthweight cases in that population that
can be attributed to illicit drug use. Estimates in this release
are based on the English and Holman (1995) derivations for the year
1992.
Reference: English, DR, Holman, CDJ, Milne, E, et al.
1995. The quantification of drug caused morbidity and mortality in
Australia, 1995 edition. Canberra: Commonwealth Department of Human
Services and Health.
31 March 1999
Further information: Geoff Sims, ph. 02 6244
1168, or Paul Williams, ph. 02 6289 6851.
For general media enquiries: Lyn Elliott, ph. 02
6244 1034.