CO validation – carbon monoxide (CO) validation is the most cost effective and least evasive method of measuring someone’s smoking status. CO validation rates are important markers of service data quality.

CO validated 4 week quitter – the national outcome measure of stop smoking services is success rates at the four week post quit date. A smoker is counted as a ‘CO validated 4 week quitter’ if s/he is a self-reported quitter and his/her expired-air CO is assessed four weeks after the designated quit date (minus three days or plus 14 days) and found to be less than 10ppm (parts per million).

Deprivation quintile – populations are divided into quintiles based on socio-economic deprivation of place of residence, with the first 20% being the least deprived and the last 20% being the most deprived. The measure of deprivation used is Index of Multiple Deprivation (IMD 2015).

Smoking prevalence (or prevalence rate) – the proportion of individuals in a population who smoke