Stephen Nash

I am a statistician working in the Department of Medical Epidemiology and Biostatistics (MEB). I specialise in clinical trial design, and also enjoy coding in Stata and teaching. I graduated with an MSc in Medical Statistics from the London School of Hygiene and Tropical Medicine in 2013. Since then I have worked at King's College London (Institute of Psychology), University College London (CRUK Cancer Trials Centre) and, from 2015-2020, in the International Statistics and Epidemiology group at LSHTM. I have also held short-term posts at the University of Oxford (The Jenner Institute) and as an education specialist at LSHTM during the Covid pandemic. I joined MEB at Karolinska Institutet in March 2023, and work in the Applied Biostatistics group.

I currently work on a number of clinical trials at MEB.

I have recently helped design two large, international, multi-year trials involving women with breast cancer. The POWER trial is testing if personalised dosing of tamoxifen will increase long-term adherence; the study leads are my colleagues Marike Gabrielson and Jenny Bergqvist. The SENOMAC-ULTRA trial, led by Jana de Boniface, is a non-inferiority trial of reduced axillary surgery. I am also the lead statistician for a cluster randomised trial (PI: Juan-Jesus Carrero) to investigate if changes to health centre IT systems can increase the detection of people with chronic kidney disease. Data collection ended in December 2025, and we hope to publish results later in 2026.

I am funded to provide one day per week support to Clinicum. This is part of a region-wide initiative between Karolinska Institutet and Region Stockholm which offers free scientific advice and provides methodological support and guidance in the planning and execution of research projects.

I have broad experience in both statistics and epidemiology, design and analysis. I particularly enjoy designing studies to make a real impact on clinical outcomes. I have co-written two Stata programs: clan, which performs cluster-level analysis on data from cluster randomised trials, and slopepower, which calculates sample size estimates for studies where the outcome is a rate over time, and you have prior data.

I teach on (and wrote the material for) the RCT section of the "Study Design and Analysis" course on the new Masters in Biostatistics and Data Science. I gave the course for the first time in December 2025.