| Study | Reason for exclusion |
|---|---|
| Ashbury 2006 | Random sample (347 completed surveys) follow up of participants 12 months post‐contest. No comparison group. |
| Chan 2012 | Follow‐on study recruiting from the Hong Kong Quit to Win series. |
| Chapman 1993 | Four‐month follow‐up of a contest, no control group |
| Cheung 2013 | Follow‐on study recruiting from the Hong Kong Quit to Win series. |
| Croghan 2001 | Before‐and‐after population‐based survey, without a control group |
| Cummings 1990 | Population‐based survey, without a control group |
| Donatelle 2000a | Target is pregnant smokers (covered by reviews in Childhood and Pregnancy Group) |
| Donatelle 2000b | Studies the use of incentives; included study in Cahill 2015 |
| Donatelle 2000c | Studies the use of incentives; included study in Cahill 2015 |
| Donatelle 2002 | Studies the use of incentives; included study in Cahill 2015 |
| Drummond 2014 | Studies the use of incentives; included study in Cahill 2015 |
| Elder 1991 | No comparison group, followed up for only 2 months. |
| Gallagher 2007 | Studies the use of incentives; included study in Cahill 2015 |
| Giné 2010 | Studies the use of incentives; included study in Cahill 2015 |
| Glasgow 1985 | Cross‐sectional survey of participants one week post‐contest; no control group |
| Gomez‐Zamudio 2004 | Interventions being tested were pharmacological aids, social support and cessation materials. No comparison group |
| Halpern 2015 | Studies the use of incentives; included study in Cahill 2015 |
| Hawk 2006 | Observational study |
| HEA 1991 | Population‐based survey, no control group |
| Heil 2008a | Studies the use of incentives; included study in Cahill 2015 |
| Higgins 2004 | Trial of contingent versus non‐contingent rewards for abstinence on pregnancy and postpartum. |
| Higgins 2004a | Studies the use of incentives; included study in Cahill 2015 |
| Higgins 2014 | Studies the use of incentives; included study in Cahill 2015 |
| Jason 1995 | Studies the use of incentives; included study in Cahill 2015 |
| King 1987 | No details of comparison community |
| Kinoshita 2004 | Overview of 3 Osaka Quit & Win contests 1998‐2000, no control groups. |
| Kira 2016 | Not a competition |
| Kollins 2010 | Not a randomized trial, and participants were followed for 24 days. |
| Korhonen 1992 | Inter‐contest comparison of TV groups; no non‐intervention control group |
| Korhonen 1993 | No non‐intervention comparison group |
| Korhonen 1998 | Evaluation of 1994 contests in Finland, Russia, Catalonia; no comparison groups |
| Korhonen 1999 | No comparison group |
| Lai 2000 | Before‐and‐after population‐based survey, without a control group |
| Lando 1990 | Comparison of 2 Minnesota contests, but only 4 to 5 months follow‐up |
| Lando 1991a | Intervention did not contain a competition. Although some participants received the Quit & Win self‐help materials, no prize was available. |
| Lando 1991b | Survey data, followed up at 3 to 4 months, without a control group |
| Lando 1995a | No comparison group |
| Lefebvre 1990 | No non‐intervention comparison group |
| Leinweber 1994 | 6‐week follow‐up, no comparison group |
| NCT01983150 | Not a competition |
| O'Connor 2006 | 11 contests in New York 2001‐2004, 4‐ to 6‐month follow‐up. No control groups |
| Ondersma 2012 | Studies the use of incentives; included study in Cahill 2015 |
| Paxton 1980 | Studies the use of incentives; included study in Cahill 2015 |
| Paxton 1981 | Studies the use of incentives; included study in Cahill 2015 |
| Paxton 1983 | Studies the use of incentives; included study in Cahill 2015 |
| Pirie 1997 | Intervention being tested was social support, not the contest itself |
| Quintiliani 2015 | Not a competition |
| Rand 1989 | Studies the use of incentives; included study in Cahill 2015 |
| Resnicow 1997 | Quit & Win surveyed as part of a multicomponent intervention, no non‐intervention control group reported |
| Roberts 1993 | Follow‐up of a pilot contest, surveyed at 4 months |
| Rooney 2005 | No non‐intervention comparison group |
| Sarraf Zadegan 2006 | International Quit & Win contests in Iran; participation and self‐reported quit rates |
| Secades‐Villa 2014 | Studies the use of incentives; included study in Cahill 2015 |
| Sheikhattari 2015 | Not a competition |
| Shoptaw 2002 | Studies the use of incentives; included study in Cahill 2015 |
| Stotts 2013 | Four‐month follow‐up |
| Tappin 2015 | Studies the use of incentives; included study in Cahill 2015 |
| Tevyaw 2009 | Studies the use of incentives; included study in Cahill 2015 |
| Tillgren 1992 | No non‐intervention control group |
| Tillgren 2000 | Contest for smoking mothers, 12‐month follow‐up, no control group |
| Tuten 2012 | Studies the use of incentives; included study in Cahill 2015 |
| Volpp 2006 | Studies the use of incentives; included study in Cahill 2015 |
| Volpp 2009 | Studies the use of incentives; included study in Cahill 2015 |
| Wang 2014 | Follow‐on study recruiting from the Hong Kong Quit to Win series |
| Wang 2015 | Follow‐on study recruiting from the Hong Kong Quit to Win series |
| Wang 2016 | Follow‐on study recruiting from the Hong Kong Quit to Win series |
| Wang 2017 | Follow‐on study recruiting from the Hong Kong Quit to Win series |
| Wang 2018 | Follow‐on study recruiting from the Hong Kong Quit to Win series |
| White 2013 | Studies the use of incentives; included study in Cahill 2015 |
| Windsor 1988 | Studies the use of incentives; included study in Cahill 2015 |
CO: carbon monoxide