Exploring the impact of public health teams on alcohol premises licensing in England and Scotland (ExILEnS): procotol for a mixed methods natural experiment evaluation.

BACKGROUND: Recent regulatory changes in the system by which premises are licensed to sell alcohol, have given health representatives a formal role in the process in England and Scotland. The degree to which local public health teams engage with this process varies by locality in both nations, which have different licensing regimes. This study aims to critically assess the impact on alcohol-related harms - and mechanisms - of public health stakeholders' engagement in alcohol premises licensing from 2012 to 2018, comparing local areas with differing types and intensities of engagement, and examining practice in Scotland and England.

METHODS: The study will recruit 20 local authority areas where public health stakeholders have actively engaged with the alcohol premises licensing system (the 'intervention') and match them to a group of 20 lower activity areas using genetic matching. Four work packages are included: (1) Structured interviews and documentary analysis will examine the type and level of intervention activity from 2012 to 2018, creating a novel composite measure of the intensity of such activity and will assess the local licensing system and potential confounding activities over the same period. In-depth interviews with public health, licensing, police and others will explore perceived mechanisms of change, acceptability, and impact. (2) Using longitudinal growth models and time series analyses, the study will evaluate the impact of high and low levels of activity on alcohol-related harms using routine data from baseline 2009 to 2018. (3) Intervention costs, estimated National Health Service cost savings and health gains will be evaluated using the Sheffield Alcohol Policy Model to estimate impact on alcohol consumption and health inequalities. (4) The study will engage public health teams to create a new theory of change for public health involvement in the licensing process using our data. We will share findings with local, national and international stakeholders.

DISCUSSION: This interdisciplinary study examines, for the first time, whether and how public health stakeholders' involvement in alcohol licensing impacts on alcohol harms. Using mixed methods and drawing on complex systems thinking, it will make an important contribution to an expanding literature evaluating interventions not suited to traditional epidemiological research.