Domain	Judgement	Support for judgement
Bias due to confounding	Moderate	Confounding expected, but sufficiently accounted for using regional controls. There were also a sufficient number of time points before and after the intervention to characterise pre‐ and postintervention trends.
Bias in selection of participants into the study	Low	Risk of selection bias is unlikely as sales data from whole regions was used.
Bias in classification of interventions	Low	Interruption time points well defined and not selected based on outcome data.
Bias in deviations from intended  interventions	Low	No particular deviations from intended intervention (introduction of heated tobacco to market).
Bias due to missing data	Low	Sales data were reasonably complete.
Bias in measurement of outcomes	Low	Recording of sales data and associated measurement error unrelated to introduction of heated tobacco to market.
Bias in selection of reported result	Moderate	Outcome measures and analyses unregistered, but clearly defined and consistent. Multiple sensitivity analyses reported, but no indication of that these were selected from among multiple analyses.