Competitions might encourage people to undertake and/or reinforce behaviour change, including smoking cessation. Competitions involve individuals or groups having the opportunity to win a prize following successful cessation, either through direct competition or by entry into a lottery or raffle.

Key results and the quality of the evidence

None of the studies in which groups of smokers competed against each other directly found that more people quit than in similar groups of smokers who were not entered into a competition. Combining the results of randomized controlled trials of lottery‐type competitions, which provide the best evidence, did not show evidence that competitions increase rates of quitting smoking. Three Quit & Win contests did find that people who were in the contest had higher quit rates than people in a comparison community, who did not take part. However, these studies were of low quality and appeared to have very little effect on the overall smoking rates in the community, as fewer than one in 500 smokers appeared to quit because of the Quit & Win contest.

Fourteen of the 20 studies included were randomized controlled trials, but many of these did not describe their methods well enough for us to decide whether they were of high quality. Overall, we judged the quality of the evidence included in this review to be very low, so we can draw no strong conclusions from the findings. It is important that any future research in this area is designed to be of high quality and is reported in detail, so that we can increase the confidence we have in our findings.