A brief intervention with a small to moderate effect size can potentially benefit a large number of smokers and increase smoking cessation within the community if it is carried out routinely in clinical practices by all or most healthcare professionals or people with minimal training. It is also the most cost-effective smoking cessation programme, because no extra or minimal funding is needed to provide the venue, manpower, and other expenses (but incentives or payments to healthcare professionals and follow-up support would be needed). There is no evidence that longer interventions are more effective than shorter interventions. Brief cessation interventions have been shown to be effective with strong evidence from the investigators' randomised controlled trials and in systematic reviews.