Project TNT was evaluated in a randomized experiment involving 6,700 seventh grade students from 48 junior high schools in Southern California and the state of Illinois. The ethnicity of the student participants was 60% white non-Hispanic, 27% Latino, 7% African American, and 6% Asian American. The evaluation study contrasted five conditions, including four curricula and a “usual school health education” control. Three curricula were designed to counteract the effects of separate (single) program components (normative social influence, informational social influence, and physical consequences), whereas a fourth, comprehensive curriculum, Project TNT, was designed to counteract all three effects.

To determine outcomes, one- and two-year follow-ups were conducted after the core 7th grade intervention was delivered. Findings showed that compared to the control condition, the program obtained significant effects on initiation and weekly use of smokeless tobacco and cigarettes. The program reduced initiation of cigarettes by approximately 26% over the control group, when one-year and two-year follow-up outcomes were averaged together. It also reduced initiation of smokeless tobacco use by approximately 30%; weekly or more frequent cigarette smoking was reduced by approximately 60%; and weekly or more frequent smokeless tobacco use was eliminated.