[BMJ Publishing Group Ltd Society for Social Medicine and Population Health and International Epidemiology Association European Congress Annual Scientific Meeting 2019, Hosted by the Society for Social Medicine & Population Health and International Epidemiology Association (IEA), School of Public Health, University College Cork, Cork, Ireland, 4–6 September 2019 - ()] Oral Presentations - OP42 How much evidence do we have, and how much more do we need for assessing the impact of public health interventions on health inequalities? Part 1: smoking cessation interventions