American biostatistics professor Liz Stuart, who was born in the Sydney suburb of Kogarah, drew an audience of about 60 people on 21st October 2019. After running a full-day and fully-subscribed short-course earlier that day she managed to stay on her feet all the way to the end.
An early example in Liz's talk concerned a health insurer that may be deciding to approve a new treatment for back pain. Of interest is the "population" average of the treatment effect.
Some of the themes of the presentation were causal inference, generalisability. For example, results from randomised trials may not generalise to the population of interest. Liz then projected a rare technical slide, concerning her work on population average treatment effect.
Problems such as biases if participation in a trial is associated with impacts were mentioned. For example, large urban school districts in the United States are more likely to participate in education studies.
Liz said that often one has to deal with the reality of only having a single randomised trial. Remedies based on Bayesian additive regression trees were discussed.
Towards the end of the presentation an example concerning highly active retroviral therapy for patients with human immunodeficiency virus was discussed. A problem was the high proportion of people in the trial being older, white and male and this tended to bias the population average treatment effect. The problem of generalising beyond the study was brought up again.
A closing quote, which summed up much of what Liz spoke about was "You can't fix by analysis what you bungled by design".
University of Technology Sydney