The Quit Line (Me Mutu) is the world's leading smoking cessation telephone line having supported over 500,000 quit attempts and over 100,000 successful quits since 2000. Consequently the QuitLine holds a large and unique dataset on case histories, successes and failures. This project will analyse the data held on these cases in order to produce an algorithm to assist smoking cessation providers in making decisions when developing appropriate advice and support to NZ quit attempters and reduce attrition. Such factors as demographics, level of addiction, motivational status and quit history will be synthesised through an algorithm in order to produce customised, risk adjusted guidance for both quitters and providers, thus improving the effectiveness and efficiency of the advice provided. The algorithm will be available to ALL smoking cessation advisors/services in NZ in order to support the goal of Smokefree Aotearoa 2025.