The effects of missing data when surveying alcohol habits
AIMS - This study aimed at describing the effects of missing data when surveying alcohol consumption using a Random Digit Dialling procedure. METHODS - Data was part of the Monitor project including repeated monthly data on the alcohol habits in the general Swedish population. Non-respondents during four months were followed up a year later and asked to do a shortened telephone interview and were compared to a concurrent sample of respondents (n=2552 versus n=6005). Further, using a second approach, the monthly levels of non-response was related to the level of measured alcohol use in a time series analysis (n=67500). RESULTS - The results indicated no differences in the level of reported alcohol or tobacco use with except for a slightly higher proportion of alcohol abstainers in the sample of initial non-response. The time series showed no pattern of co-variation between the obtained nonresponse levels and the assessed levels of alcohol or tobacco use. CONCLUSIONS - On the basis of the results it was meaningful to make a distinction between "soft" non-respondents (responding after extensive contacting effort) and "hard" non-respondents (not responding albeit extensive effort) and the results suggest that inclusion of the "soft" non-respondents does not by necessity lead to higher levels of assessed alcohol use.
Håkan Källmén, Kristina Sinadinovic, Anne Berman and Peter Wennberg
Risky drinking of alcohol in Sweden: A randomized population survey comparing web- and paper-based self-reports
AIMS - This study compared data quality and response rates for the Alcohol Use Disorders Identification Test (AUDIT) in a web-based versus in a paper-and-pencil format survey. SETTING - Subjects were randomised to one of two parallel samples, one web-based and the other paper-based. Data were collected during 2009. RESULTS - The web-based format yielded a lower response rate compared to the paper version (26.2% vs. 53.6%), internal consistency was quite similar (0.82 vs. 0.77), while the mean AUDIT scores were higher in the web-based format for both men and women. Conclusions - Future studies should focus on methods for combining different administration methods in order to maximize response rates.
Anders Romelsjö, Anna-Karin Danielsson, Peter Wennberg and Björn Hibell
AIMS – To study the prevalence of cannabis use and drug-related problems among European adolescents and the utility of the prevention paradox. METHODS – Survey data from the European School Survey Project on Alcohol and Other Drugs (ESPAD) in 2007 in the 27 countries with information about drug use and drug-related problems was used. We analysed the proportion of all drug-related problems that occurred in a high risk group and among others who had used cannabis in the previous 12 months. The cut-off for the high risk group was chosen to include 10-15 % of the most frequent cannabis users. RESULTS – The high risk groups accounted for a substantial, but a minority, of drug-related problems among boys as well as girls. A minority of those who had used cannabis reported any drug-related problem. The proportion of adolescents with drug-related problems and the average number of problems increased with frequency of cannabis use. CONCLUSIONS – We find support for policy measures of more general character, supported by the prevention paradox. However, this does not exclude a policy supporting frequent drug users if they can be identified