Table 1.

Characteristics of Three Smoking Cessation Studies Using Fully Crossed Factorial Designs

	Maintenance Intervention Screening Experiment	Motivation Screening Experiment	Population Based Study
Study Reference	Schlam et al., 2016	Cook et al., 2016	Fraser et al., 2014
ClinicalTrials.gov	NCT01120704	NCT01122238	Exempt
Participants	N=513 adult daily smokers recruited in 11 primary care clinics	N=517 adult daily smokers recruited in 11 primary care clinics	N=1034 adult daily smokers recruited over the internet
Study Design	2x2x2x2x2 fully crossed factorial design Each factor had 2 levels ON and OFF All participants received a base cessation treatment (8 weeks of nicotine patch + nicotine gum, and counseling totaling 50 min across four contacts from Week -1 prequit through Week 2 postquit)	2x2x2x2 fully crossed factorial design Each factor had 2 levels ON and OFF Initial 6-week motivation-phase treatment period, with option to extend the same treatment for another 6 wks Option to enter cessation treatment at any time in the 6-month study period	2x2x2x2x2 fully crossed factorial design Each factor had 2 levels ON and OFF (or ‘lite’)
Assessments	Baseline measures included demographics, smoking history, smoking dependence and motivation Smoking withdrawal, motivation, affective variables, adherence to counseling and medication, and smoking status were recorded throughout treatment.	Baseline measures included demographics, smoking history, smoking dependence and motivation Smoking withdrawal, motivation, affective variables, adherence to counseling and medication, and smoking status were recorded throughout treatment	Baseline measures included demographics, smoking history, smoking dependence and motivation Email assessments at postquit weeks 1–3 and at 1, 3, and 7 months Assessments included smoking status, withdrawal, affect, smoking dependence, and access to and use of quitting resources
Outcomes	Point-prevalence abstinence at week 52	Quit attempts, smoking reduction, and point-prevalence abstinence at 6, 12, and 26 weeks depending on the outcome	Point-prevalence abstinence at 1, 3, and 7 months follow-up.
Factors	Extended Medication:   ON: 26 weeks of nicotine patches plus nicotine gum   OFF: 8 weeks of nicotine patches plus nicotine gum Medication Adherence Counseling:   ON: Two 10-minute in-person sessions (Weeks -1 and 1) that provided information tailored to correct misconceptions regarding cessation   OFF: No counseling sessions Automated Adherence Calls:   ON: 7-11 brief automated medication reminder and motivation calls   OFF: No automated adherence calls Electronic Medication Monitoring:   ON: A “Helping Hand” (HH) gum dispenser electronically recorded gum use plus printouts of daily gum use and 5-9 adherence counseling sessions OFF: Participants carried the HH to record gum use; no gum use printouts or associated counseling Maintenance Counseling:   ON: Eight 5-10 min calls   OFF: No maintenance counseling	Nicotine Patch: ON: 6 weeks of daily 14-mg nicotine patches OFF: No nicotine patches Nicotine Gum: ON: 6 weeks of 2-mg nicotine gum OFF: No nicotine gum Behavioral Reduction (BR): ON: One initial 20-minute in-person BR counseling session followed by six weekly 10-minute counseling calls designed to reduce smoking OFF: No BR counseling Motivational Interviewing (MI): ON: One initial 20-minute in-person MI counseling session followed by three biweekly, 10-minute counseling calls over the 6-week intervention period designed to enhance intrinsic motivation to reduce smoking and quit OFF: No MI counseling	Web Site Intervention: ON: National Cancer Institute (NCI) Smokefree.gov website (step-by-step quit guide, motivational content, skill training, and interactive features) OFF: A brief, ‘lite’ version of the website; no skill-training content Quitline Counseling: ON: Five scheduled 15-30-minute proactive counseling calls from the NCI Information Service Quitline OFF: No calls Cessation Brochure: ON: The NCI Clearing the Air brochure OFF: A brief or ‘lite’ 12-page booklet; no active behavior change content Text Messaging: ON: E-mailed messages were sent for a total of 12 weeks; messages offered quitting tips, motivational content, and stressed use of treatment resources OFF: No messages Cessation Medication: ON: Mailed, 2-week “starter kit” of nicotine mini-lozenges OFF: No pharmacotherapy

Note. All three experiments were conducted in accordance with the provisions of the World Medical Association Declaration of Helsinki; the Maintenance and Motivation studies were approved by an institutional review board; the Population study was exempt from review.