An exploration of the missing data mechanism in an Internet based smoking cessation trial

Table 3 The outcome Y by the number of contact attempts and trial arm

Attempts	Participants	Responded	Of responders % quit
One phone call	217	214	50/214=23.4%
One phone call and an email	925	69	30/69 =43.5%
Two phone calls	134	132	23/132=17.4%
Two phone calls and an email	6	1	0/1=0%
Three phone calls	93	89	16/89=18.0%
Three phone calls and an email	3	0	0/0
Four phone calls	59	57	10/57=17.5%
Four phone calls and an email	4	0	0/0
Five phone calls	48	45	9/45=20.0%
Five phone calls and an email	8	0	0/0
Six phone calls	19	19	1/19=5.3%
Six phone calls and an email	2	1	1/1=100%
Seven phone calls	38	38	5/38=13.2%
Seven phone calls and an email	2	0	0/0
Eight phone calls	17	16	3/16=18.8%
Eight phone calls and an email	5	1	1/1=100%
Nine phone calls	11	10	2/10=20%
Nine phone calls and an email	2	0	0/0
Ten phone calls	19	19	6/19=31.6%
Ten phone calls and an email	146	11	5/11=45.5%

The fraction and percentage of participants who successfully quit smoking (Y=1) are tabulated by the number of contact attempts (telephone calls and email). Participants received up to ten telephone calls and up to one email attempt.

ISSN: 1471-2288