These programs identified some effe

These programs identified some effective components
of drug-use prevention; however, they mentioned
little about the theoretical constructs that were
the basis for the development and evaluation of programs,
especially with regard to measurements of
theoretical constructs. Most were not well developed
operationally, whereas the theory of planned behavior
(TPB) has published manuals about its theoretical
concepts and multivariate measurements.
The TPB focuses on theoretical constructs for
individual motivational factors that determine the
likelihood of performing a behavior (behavioral intention),
which is theorized to directly predict behavioral
initiation.8,9 Human behaviors are not completely
under volitional control and behavioral intention is
determined jointly by attitude, subjective norm, and
perceived behavioral control (PBC).8 The TPB is empirically
supported and provides a framework for investigating
behavioral intention, behavioral initiation, and
behavior itself.10 McMillan and Connor have used the
TPB to investigate the factors underlying intention to
use and self-reported use of alcohol, tobacco, and illicit
drugs.11,12