Table 4.

Summarization of main findings.

Research Question	Main Findings
1. Why do smokers decide to try using ENDS or not try using ENDS?	All groups were initially interested in ENDS because of smoking cessation beliefs.
	Perceived convenience made trying ENDS appealing for all groups.
	Risk perceptions may deter or encourage trying or re-trying ENDS.
	Cost relative to cigarettes deterred some from trying or re-trying ENDS and not others.
2. What factors drive dual users of cigarettes and ENDS to use both products rather than switching completely to ENDS?	Dual Users were motivated to continue ENDS use because of convenience.
	Dual Users found ENDS flavors appealing.
	ENDS were not satisfying enough to support switching for Dual Users.
	Product problems prevented Dual Users from switching completely to ENDS.
3. What factors drive smokers who have initiated ENDS use to discontinue and return to smoking cigarettes?	Rejectors did not find ENDS satisfying enough.
	Rejectors were frustrated by ENDS product problems.
	Rejectors perceived ENDS as more expensive than cigarettes.
	Rejectors were concerned about the health risks of ENDS.
4. What factors facilitate a successful transition from cigarette smoking to exclusive ENDS use?	Switchers found ENDS to be a satisfying replacement for cigarettes.
	Switchers perceived ENDS as less harmful to their health than cigarettes.
	After some trial and error, Switchers found an ENDS product that fit their needs.
	Switchers found ENDS flavors appealing.