Estimation of illicit drug use among high school students in the Silesian voivodship (Poland) with the use of the randomized response technique

ABSTRACT The prevalence of illicit drug use among high school students living in the Silesian voivodship (Poland) is estimated using either the random response techniques of forced response design or the Liu-Chow method. Respondents answer a sensitive question only with a certain probability, thus ensuring anonymity. These methods provide correct estimates of prevalence, unlike interviews based on anonymous questionnaires, which can lead to underestimate the prevalence. Compared with those obtained with anonymous questionnaires, the results obtained with the forced response method are that 10.7 times more high school students used the new psychoactive substances, 6.0 times more amphetamines, methamphetamines, and others, 3.1 times more heroin or morphine, and 1.6 times more marijuana or hashish. The Liu-Chow method provides an estimate of 10.7% of respondents who reported using new psychoactive substances, while the estimate by the anonymous questionnaire is only 1.5%. In the case of marijuana or hashish, the Liu-Chow method gives an estimate of 37.0% of users, while the estimate with anonymous questionnaires is only 22.0%.