Table 2. Smokers by usual brand cigarette “tar” category ^a .

“Tar” category	TH	S	TB	Overall
Intent-to-treat sample
Full flavor b	17	15	19	51
Full flavor low machine yield c	25	26	24	75
Ultra-low machine yield d	1	1	1	3
Per-protocol sample
Full flavor b	14	10	16	40
Full flavor low machine yield c	17	9	18	44
Ultra-low machine yield d	1	0	1	2

TH, switched to tobacco-heating cigarette; S, switched to snus; TB, switched to ultra-low machine yield tobacco-burning cigarette.

^a“Tar” category as determined by the Cambridge Filter Method (CFM) (FTC, 1967, 1980). CFM “tar” ratings for two brands (subjects) were unknown.

^b>13 mg CFM “tar”.

^c6–13 mg CFM “tar”.

^d<6 mg CFM “tar”.