Affiliations: [a] Substance Abuse and Mental Health Services
Administration, Rockville, MD, USA | [b] Statistics Research Division, RTI International**,
Research Triangle Park, NC, USA | [c] Survey Research Division, RTI International**,
Research Triangle Park, NC, USA
Correspondence:
[*]
Corresponding author: Douglas Wright, Substance
Abuse and Mental Health Services Administration, Office of Applied Studies, 1
Choke Cherry Road, Room 7-1019, Rockville, MD 20850, USA. Tel.: +1 240 276 1259;
Fax: +1 240 276 1260; E-mail:
[email protected]
Abstract: The purpose of this paper is to determine whether giving a monetary incentive has
an effect on reported drug use rates. Sampling weights were adjusted to account
for the differential response rates between the incentive and non-incentive
cases. Then logistic regression models of substance use were fitted as a
function of the incentive level ($0, $20, and $40) while controlling on other
variables that might mask the relationship. The incentive had a statistically
significant effect on the reported past-year use of marijuana and on past-month
use of cocaine, but no effect on past-month or lifetime use of marijuana.
Offering a monetary incentive to respond can result in different estimated
prevalence rates for the incentive and non-incentive groups. The extent of the
difference may be a function of the perceived level of social disapproval of the
substance and the reference period (past month, past year, or any past use).
Some of the difference appears to be due to differences in substance use rates
between the group that had traditionally reported without an incentive and the
new group attracted by the incentive. Other differences appear to result from
more honest reporting among the traditional respondents.
