. 2017 Nov 21;17:890. doi: 10.1186/s12889-017-4902-7

Table 4.

Recommendations compared to the Russell standard

	Russell standard		Findings		Recommendations (Russell 2.0)
Self-report	Prolonged abstinence	Over the whole follow-up period	Prolonged abstinence	6 or/and 12 months	Prolonged abstinence	6 or/and 12 months
			Point prevalence abstinence	7 days^a	Point prevalence abstinence	7 days^a
			Continuous abstinence	6 months^a
			Number of cigarettes smoked	7 days^a	Number of cigarettes smoked	7 days^a
Grace period		Undefined		Undefined		Two weeks
Biochemical validation	Carbon monoxide	(9 p.p.m. in) expired air	Carbon monoxide	expired air
			Cotinine^b	saliva^a	Cotinine^b	(15 ng/ml in) saliva^a
Follow-up		6 or/and 12 months		6 or/and 12 months		6 or/and 12 months

^aDifferent from the Russell standard

^bUse biochemical validation in new product and harm-reduction studies