BMC Public Health 2007, 7:352 http://www.biomedcentral.com/1471-2458/7/352 Future research should assess which specific message con- tent of radio and television campaigns has the highest recall, and investigate which specific messages – or com- binations of messages – have the largest effect on condom use. Doing so will require having detailed information about program content and about broadcast schedules, which will facilitate the design of survey questionnaires that better capture the frequency and nature of program exposure. This in turn will require close collaboration between program staff and researchers. Evaluations of the impact of mass media campaigns can be further strength- ened by using a panel study design, including both a pre- and a post-intervention assessment. Although it is typi- cally not feasible to implement such studies on a large scale, it may be helpful to implement them on a smaller scale for the specific purpose of enhancing our under- standing of what message contact works best. Competing interests The author(s) declare that they have no competing inter- ests. Authors' contributions DM conceived of the study and drafted the background section and discussion and conclusions. RV developed the study design, carried the statistical analysis, and drafted the methods and results sections. Both authors read and approved the final manuscript. Acknowledgements This study was funded by the United States Agency for International Devel- opment (USAID), through a grant from the MEASURE Evaluation project (Task Order #3933). The authors are grateful to N'Della N'Jie and Leslie Ornsteen for assistance with literature searches and reviews, to Sohail Agha and David Guilkey for comments and suggestions, and to Susan Berg- man for editing. References 1. Agha S: Sexual Activity and Condom Use in Lusaka, Zambia. International Family Planning Perspectives 1998, 24:32-7. 2. Central Statistical Office [Zambia], Central Board of Health [Zambia], ORC Macro: Zambia Demographic and Health Survey, 2001–2002. Lusaka, Zambia, and Calverton, MD: Central Statistical Office, Zambia, Central Board of Health, Zambia, and ORC Macro; 2003. 3. Chikamata DM, Chinganya O, Jones H, RamaRao S: Dual Needs: Contraceptive and Sexually Transmitted Infection Protec- tion in Lusaka, Zambia. International Family Planning Perspectives 2002, 28:96-104. 4. Slaymaker E, Buckner B: Sexual behaviour and HIV prevalence in Zambia: 1996–2003. In Workshop on Measurement of Sexual Behaviour in the Era of HIV/AIDS.; London London and Chapel Hill, NC: Centre for Population Studies, London School of Hygiene and Tropi- cal Medicine and Carolina Population Center, University of North Carolina; 2003. 5. van den Borne F, Tweedie IA, Morgan WB: Family Planning and Reproductive Health in Zambia Today. Baltimore: The Johns Hopkins School of Public Health Center for Communication Pro- grams; 1996. 6. Yoder PS, Hornik R, Chirwa BC: Evaluating the Program Effects of a Radio Drama about AIDS in Zambia. Stud Fam Plann 1996, 27:188-203. 7. Colorito R: Soap Opera Series With a Soul. 2003. 8. Communication Initiative: HIV/AIDS Prevention Public Service Announcements – Zambia. 2003 [http://www.comminit.com]. 9. Population Services International (PSI): Where we work: Zambia. 2007 [http://www.psi.org/where_we_work/zambia.html]. 10. Underwood C, Hachonda H, Serlemitsos E, Bharath U: Impact of the Heart Campaign. Findings from the Youth Surveys, 1999 & 2000. Baltimore, MD: Johns Hopkins Center for Communication Programs; 2001. 11. Underwood C, Hachonda H, Serlemitsos E, Bharath-Kumar U: Reducing the Risk of HIV Transmission Among Adolescents in Zambia: Psychosocial and Behavioral Correlates of View- ing a Risk-Reduction Media Campaign. J Adolesc Health 2006, 38:55-68. 12. Dzekedzeke K: Estimation of HIV Prevalence in the Zambian Monitoring System. In Joint Tropical Disease Research Centre Ndola/ UNAIDS/WHO Technical Meeting on Reconciling Survey and Surveillance- based HIV Estimates.; Lusaka, Zambia Lusaka, Zambia: Joint Tropical Disease Research Centre Ndola/UNAIDS/WHO; 2003. 13. Fylkesnes K, Musonda RM, Kasumba K, Ndhlovu Z, Mluanda F, Kae- tana L, Chipaila CC: The HIV Epidemic in Zambia: Socio- Demographic Prevalence Patterns and Indications of Trends among Childbearing Women. AIDS 1997, 11:339-45. 14. Family Health International: Round 1 Behavioral Surveillance Survey, Zambia. Long Distance Truck Drivers. Rosslyn, VA: Family Health International/USAID IMPACT Project; 2000. 15. Family Health International: Round 1 Behavioral and Biologic Surveillance Survey, Zambia: Female Sex Workers. Rosslyn, VA: Family Health International/USAID IMPACT Project; 2000. 16. World Health Organization: HIV/AIDS Epidemiological Surveil- lance Update for the WHO African Region, 2002. Harare, Zimbabwe: World Health Organization; 2003. 17. Gaisie K, Cross A, Nsemukila G: Zambia Demographic and Health Survey, 1992. Columbia, MD: University of Zambia, Cen- tral Statistical Office, and Macro International Inc; 1993. 18. Central Statistical Office [Zambia], Ministry of Health [Zambia], Macro International Inc: Zambia Demographic and Health Sur- vey, 1996. Calverton, MD: Central Statistical Office and Macro International Inc; 1997. 19. Magnani RJ, Karim AM, Weiss LA, Bond KC, Lemba M, Morgan GT: Reproductive Health Risk and Protective Factors Among Youth in Lusaka, Zambia. J Adolesc Health 2002, 30:76-86. 20. Zambian PWAs become peer educators. AIDS Anal Afr 1994, 4(5):6. 21. USAID Zambia: Development Challenges. 2000 [http:// www.usaid.gov/locations/sub-saharan_africa/countries/zambia/]. 22. Mahler K: Convert Method Use Among Urban Zambian Women Is Tied to Poor Spousal Communication on Contra- ception. International Family Planning Perspectives 1999, 25:103-4. 23. Population Council: Population Council- Zambia. 2007 [http:// www.popcouncil.org/africa/zambia.html]. 24. Skibiak J: An assessment of the need for contraceptive intro- duction in Zambia (WHO/HRP/ITT/95.4). World Health Organization; 1995. 25. Barnett B: Programs for Adolescents: Reproductive Health Merit Badge for Scouts. Network 2000:20. 26. Goodrich R: AIDS and behaviour change in Zambia. AIDS Anal- ysis Africa 1998:5-8. 27. Kambou SD: The Evolution and Application of Participatory Learning and Action in the Partnership for Adolescent Sex- ual and Reproductive Health (PALS) Project. Lusaka, Zambia, and Washington, D.C. CARE International and FOCUS on Young Adults; 1999. 28. Pillai VK, Barton TR: Sexual Activity Among Zambia Female Teenagers: The Role of Interpersonal Skills. Adolescence 1999, 34:381. 29. Shannon A: Advocating for Adolescent Reproductive Health in Sub-Saharan Africa. Washington, D.C.: Advocates for Youth; 1998. 30. Media Materials Clearinghouse: Your Health Matters: Youth in Crisis. 2007 [http://www.m-mc.org]. 31. Media Materials Clearinghouse: "Our Neighborhood" and "Com- munity Health with Sister Evelina". 2007 [http://www.m- mc.org]. 32. Media Materials Clearinghouse: X-plosion no.1. 2007 [http:// www.m-mc.org]. Page 11 of 12 (page number not for citation purposes)