ASSIST (A Stop Smoking in Schools Trial)

Randomised controlled trial of the effectiveness of a schools-based, peer-led, smoking intervention


Smoking is the largest single cause of preventable illness in the UK, but whilst adult smoking prevalence has been falling, smoking amongst teenagers has risen over the last decade. Much money, time and effort is spent on anti-smoking programmes in UK schools, yet there is no rigorous evidence to support the effectiveness of any of these programmes.

This project evaluated a different approach, which was not classroom-based or teacher-delivered. Instead, peer-nominated students in Year 8 (aged 12-13) were recruited as 'peer supporters' and given intensive training off the school premises by professional health promotion staff. The peer supporters were trained to intervene informally with their Year 8 peers in everyday situations to discourage them from smoking (Audrey et al., 2004). This approach was based on that used in a successful intervention to reduce unsafe sexual practices among gay men ( Prior to the full-scale trial, the approach had been tested in a feasibility study conducted in four South Wales schools in the mid 1990's (Bloor et al, 1999).

Study Design

The large-scale effectiveness trial, known as ASSIST, was funded by a grant of £1.5m from the Medical Research Council, and was led by Prof Rona Campbell and Professor Laurence Moore. The project aimed to test the effectiveness of the intervention using a pragmatic cluster randomised trial design. Fifty-nine schools in South East Wales and the West of England were randomly allocated either to continue with their normal smoking education programme, or to do so with the additional peer supporter programme.

Students were followed up for two years to assess whether smoking prevalence in the intervention schools was lower than that in the schools which did not receive the programme. In addition, the study involved a substantial component of process evaluation, and an economic evaluation to assess the gains of the intervention against the costs of achieving them.


The results suggest that, if implemented on a population basis, the ASSIST intervention could lead to a reduction in adolescent smoking prevalence of public-health importance.


Further Resources:


  • White J, Holliday J, Daniel R, Campbell R, Moore L. Diffusion of effects of the ASSIST school-based smoking prevention intervention to non-participating family members: a secondary analysis of a randomised controlled trial . Addiction. 2019 Oct 26.
  • Dobbie F, Purves R, McKell J, Dougall N, Campbell R, White J, Amos A, Moore L, Bauld L.   Implementation of a peer-led school based smoking prevention programme: a mixed methods process evaluation.  BMC Public Health.  2019 Jun 13; 19 (742).  Available from:
  • Dobbie F, Purves R, McKell J, White J, Campbell R, Amos A, Moore L, Bauld L. A Stop Smoking in Schools Trial (ASSIST) a decade on: insights from a mixed method process evaluation. Tob Induc Dis. 2018;16(Suppl 1):A423. Available from:
  • White J, Hawkins J, Madden K, Grant A, Er V, Angel L, Pickles T, Kelson M, Fletcher A, Murphy S, Midgely L, Eccles G, Cox G, Hollingworth W, Campbell R, Hickman M, Bonell C, Moore L. Adapting the ASSIST model of informal peer-led intervention delivery to the Talk to FRANK drug prevention programme in UK secondary schools (ASSIST+FRANK): intervention development, refinement and a pilot cluster randomized controlled trial. Public Health Res. 2017 Oct. 5(7).
  • Hollingworth W, Cohen D, Hawkins JE, Hughes R, Moore LAR, Holliday J et al. Reducing smoking in adolescents: cost-effectiveness results from the cluster randomised ASSIST (a stop smoking in schools trial). Nicotine and Tobacco Research. 2012;14(2):161-168.
  • Starkey FA, Audrey S, Holliday JC, Moore LAR, Campbell R. Identifying influential young people to undertake effective peer-led health promotion: the example of A Stop Smoking In Schools Trial (ASSIST). Health Education Research. 2009 Aug;24(6):977 - 988.
  • Holliday JC, Audrey S, Moore LAR, Parry-Langdon N, Campbell R. High fidelity? How should we consider variations in the delivery of school-based health promotion interventions? Health Education Journal. 2009 Jan;68(1):44 - 62.
  • Campbell R, Starkey FA, Holliday J, Audrey S, Bloor M, Parry-Langdon N et al. An informal school-based peer-led intervention for smoking prevention in adolescence (ASSIST): a cluster randomised trial. Lancet. 2008 May 10;371(9624):1595 - 1602.
  • Audrey S, Holliday J, Campbell R. Teachers' perspectives on the implementation of an effective school-based, peer-led smoking intervention. Health Education Journal. 2008 Jun;67(2):74 - 90.
  • Audrey S, Holliday J, Parry Langdon N, Campbell R. Meeting the challenges of implementing process evaluation within randomised controlled trials: the example of ASSIST (A Stop Smoking In Schools Trial). HER. 2006 Jul;21(3):366 - 377.
  • Audrey S, Holliday J, Campbell R. It's good to talk: Adolescent perspectives of an informal, peer-led intervention to reduce smoking. Social Science and Medicine. 2006 Jul;63 (2):320 - 334.
  • Starkey FA, Moore LAR, Campbell R, Sidaway MP, Bloor M. Rationale, design and conduct of a comprehensive evaluation of a school-based peer-led anti-smoking intervention in the UK: the ASSIST cluster randomised trial BioMed Central. 2005.
  • Audrey S, Cordall KM, Moore L, Cohen D, Campbell R. The development and implementation of a peer-led intervention to prevent smoking among secondary school students using their established social networks. Health Education Journal. 2004 Apr;63(3):266 - 284.
  • Parry-Langdon N, Bloor M, Audrey S, Holliday J. Process evaluation of health promotion interventions. Policy and Politics. 2003;31(2):207 - 216.


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