Exploring general practitioners' perspectives about using N-of-1 trials in general practice: A theory-based interview study

About this study

The randomised controlled trial (RCT) is recognised as the “gold standard” design for evaluating interventions. RCTs tell us whether a treatment is effective on average, but not whether it is effective for an individual patient. In contrast, N-of-1 trials are multiple crossover, randomised controlled trials of treatments versus a placebo (or another treatment) in a single patient that can be used to determine treatment response at the individual patient level. Individualised findings from N-of-1 trials provide greater precision in treating compared to the informal ‘trial-and-error’ approach. 

This study aims to explore General Practitioners' perspectives about the barriers and facilitators to using N-of-1 trials in general practice. The findings from the study will be used to inform strategies to increase awareness and uptake of N-of-1 trials in general practice. 

This study is embedded within a larger programme or research that explores various stakeholders' perspectives about using N-of-1 trials and single-case designs in the context of healthcare. Stakeholder groups include health professionals (e.g. GPs, psychologists, physiotherapists), patients, trialists/methodologists, biostatisticians, journal editors, ethics board members and health research funders. 

Ethical Approval

This study adheres to the Guidelines of the ethical review process of The University of Queensland and the National Statement on Ethical Conduct in Human Research. Ethics ID: 2019/HE002372.


Mayne Bequest, Mayne Academy of General Practice, The University of Queensland (2021).  

Prinicipal investigator

Dr Suzanne McDonald

Research Fellow (Health Services Researcher)
General Practice Clinical Unit
Sessional Academic
School of Psychology

UQ Co-investigators

Dr David King

Clinical Senior Lecturer
General Practice Clinical Unit
Dr Jane Nikles

Dr Jane Nikles

Senior Research Fellow
UQ Centre for Clinical Research

External Co-investigators

 Associate Professor Justin Presseau

 School of Epidemiology & Public Health, University of Ottawa