Abstract
Aims: The objective of our research was to study the influence of the message credibility (according to its mode of transmission) and the pressure to hide consumption (the use of anonymous or named questionnaires) regarding the effectiveness of the 'Bogus Pipeline', a frequently used resource to increase the honesty of self-reports of tobacco consumption among adolescents. Design: Random assignment of 18 classes (previously divided into two groups) to six experimental conditions (six groups per condition): 'Bogus Pipeline' with video presentation and anonymous questionnaire; 'Bogus Pipeline' with video presentation and named questionnaire; 'Bogus Pipeline' with oral presentation and anonymous questionnaire; 'Bogus Pipeline' with oral presentation and named questionnaire; 'without Bogus' and with anonymous questionnaire; and 'without Bogus' and with named questionnaire. Setting and participants: Students ( n = 504) from three middle schools in Granada, Spain. Measurement: Self-reported smoking consumption. Findings: The presentation of the message through a video is more effective than the exclusively oral presentation. The 'Bogus Pipeline' technique is effective when there is pressure to hide tobacco consumption. Conclusion: The 'Bogus Pipeline' technique is particularly effective in conjunction with a video presentation and when there is pressure to hide smoking.