Halpern 2018.

Study characteristics
Methods	Design: Randomized clinical trial Recruitment: Eligible participants were employees and their spouses at 54 companies that used Vitality wellness programs Setting: Online resources via workplace setting (54 companies), USA Study start date: First phase of recruitment October 2014, second phase November 2015 (to meet recruitment target); Study end date: 20 April 2017
Participants	Total N: 6006 N per arm: Usual care: 813; Free e‐cigarettes: 1199; Free cessation aids: 1588; Reward incentives plus free cessation aids: 1198; Redeemable deposit plus free cessation aids: 1208. Inclusion criteria: At least 18 years old Reported current smoking on a health risk assessment within the previous year Employees and their spouses that used Vitality wellness programs Exclusion criteria: Participants who express wanting to opt out of this program will be un‐enroled and excluded 51.1% women; median age 44; median cpd 10 Ecig use at baseline: 10.7% current use; 23.1% past but not current use; 39.7% never used ECs Motivated to quit: Unselected sample (total sample): 9.2% no plan to quit; 61.6% want to quit later; 27.7% want to quit/need help
Interventions	EC: Cig‐a‐like a) Usual care: Standardized Vitality program aimed at promoting tobacco cessation. This program includes existing employee benefits for quitting and the use of text/email messages to encourage tobacco cessation b) as (a), plus free EC: Free NJOY e‐cigarettes (including battery sticks, a USB charger, and up to 20 chambers with 1.0 to 1.5% nicotine per week in participants’ chosen flavors). Use of all products was free until 6 months after the quit date c) as (b) plus access to free NRT, bupropion or varenicline d) as (c) plus incentives across 6 m for testing negative for tobacco use e) as (c) plus provide money at start and lose money from this fund if they do not test negative across 6 m
Outcomes	Months 1, 3, 6 and 12 Cessation: Sustained smoking abstinence for 6 months, biochemical validation (urine cotinine, anabasine and blood carboxyhemoglobin) Other outcomes measured: Costs
Study funding	"Supported by a grant from the Vitality Institute to the University of Pennsylvania Center for Health Incentives and Behavioral Economics."
Author declarations	"Disclosure forms provided by the authors are available with the full text of this article at NEJM.org. Check these and: Dr. Troxel reports other from VAL Health, outside the submitted work. Dr. Volpp reports grants and personal fees from CVS Health, personal fees from VAL Health, grants from Humana, grants from Merck, grants from Weight Watchers, grants from Hawaii Medical Services Association, grants from Oscar Health Insurance, outside the submitted work. All of the other authors state that they have nothing to disclose."
Notes	New for 2020 update. Study listed as ongoing study NCT02328794 in 2016 review update Only arms (a) and (b) included in our analyses.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not specified
Allocation concealment (selection bias)	Unclear risk	Not specified
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not blinded and different amounts of support given to each group
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Biochemical validation
Incomplete outcome data (attrition bias) All outcomes	High risk	At 12 months very low numbers completed biochemical validation. Submitted a sample n = CG:1, free e‐cigs;4, free cessation:5, rewards: 14, deposits:16
Selective reporting (reporting bias)	Low risk	Expected outcomes reported and checked with trial registration