Gilbert 2017.

Study characteristics
Methods	Design: Randomized controlled trial Setting: General practices in England, UK Recruitment: People who were currently smoking were identified from medical records in participating practices and sent an invitation letter
Participants	4384 adults who smoked, 50% M, av. age 49, av. cpd 16 99 general practices in 18 Stop Smoking Service areas
Interventions	Intervention: participants received a brief personalized and tailored letter sent from the GP that included information specific to the participant and a personal invitation to attend a “come and try it” taster session for cessation services Control: participants received a standard generic letter from the GP practice, which advertised the local SSS and asked the participant to contact the service to make an appointment to see an adviser
Outcomes	3m prolonged abstinence at 6m Validation: Salivary cotinine level < 12 ng/mL Quit attempts
Funding Source	This study was funded by the National Institute for Health Research Health Technology Assessment Programme (project number 08/58/02).
Author's declarations of interest	QUOTE: "Irwin Nazareth is a member of the National Institute for Health Research Health Technology Assessment Funding Commissioning Panel.
Notes	Strategy: Tailored materials Level: Patients Comparison type: Single component vs. standard care
Risk of bias
Bias	Authors' judgement	Support for judgement
Sequence Generation	Low risk	Computer‐generated permutated block randomization
Allocation concealment	Low risk	Allocated by computer after participant consented
Blinding of outcome assessors All outcomes	Low risk	Abstinence was biochemically validated. Participant contact was minimal in both groups.
Incomplete outcome data All outcomes	Low risk	The overall loss to follow‐up was 23.1% (n = 1012/4384); 23.4% (n = 616/2636) in the intervention group and 22.7% (n = 396/1748) in the control group were lost to follow‐up at 6 months