Chair and Discussant: Karla Hemming, PhD University of Birmingham Session 5.1 Optimality in stepped wedge cluster randomized trials – when and where to take measurements Society of Clinical Trials and International Methodology Conference Introduction to me.. Thanks so much for the invitation. Love study design, particularly experimental design Background and lots of training at LSHTM Will give a little introduction to my academic home Am asst prof of Biostatistics and Global Health Chair and Discussant: Karla Hemming, PhD University of Birmingham

Session Overview Introduction to the session (Alan Girling) Three presentations by (~20 mins each) Exploring the relative contributions from multiple-periods - Jessica Kasza Linking contributions to comparative efficiency with other multiple-period designs – Jennifer Thompson Developing more efficient multiple-period designs - Richard Hooper