Introduction to Interrupted Time Series Analysis (ITSA)

This session is part of the ESRC Centre for Society and Mental Health's Research Methods Primer and Provocation series. In this session, Rosanna Hildersley will introduce Interrupted Time Series Analysis (ITSA), a quasi-experimental approach to data analysis and study design. ITSA specifically looks at changes associated with a specific time point, such as the introduction of a new policy, when the outcome of interest is continually measured before and after the intervention. First, she will discuss the basic underlying theory and assumptions accompanying ITSA, including what sort of questions this approach can answer, what type of data is appropriate and how the analysis works. Then, she will discuss the basic mechanics of running an ITSA using STATA, with reference to published or under review examples that Rosanna has worked on. Overall, she will provide you with the basic tools to consider how an ITSA approach could be used in your research project and demystify this approach that is often underutilised in health research. Rosanna Hildersley is currently a PhD student in the Department of Psychological Medicine and affiliated with the ESRC Centre for Society and Mental Health. She previously received her MSc in Public Health from the London School of Hygiene and Tropical Medicine in 2019 before working as a Research assistant in the Department of Health Service and Population Research. She has previously published work using a quasi-experimental approach looking at the effect of the UK COVID-19 lockdown policies on both perinatal mental health and ethnic inequality in mental health admissions. Chaired by: Professor Jayati Das-Munshi, Professor of Social & Psychiatric Epidemiology, King's College London