new paper: Hypothetical case replacement can be used to quantify the robustness of trial results.” Journal of Clinical Epidemiology

[Ken Frank]

We have a new paper out in the Journal of Clinical Epidemiology that applies sensitivity analysis to analyses of dichotomous outcomes.  The existing Fragility Index quantifies how many treatment cases with positive outcomes you'd have to switch to treatment cases with negative outcomes to change the inference that a treatment was effective.  But this does not account for the prevalence of positive or negative outcomes.  Our approach asks how many of the treatment cases with positive outcomes you'd have to replace with control cases to generate the necessary switches.  

For example, you would have to replace more than 2,600 vaccinated cases who did not get sick in the Moderna trials to generate about 35 switches of vaccinated with no infection to vaccinated with infection  to change the inference that Moderna is effective at at least the 70% level.  About the same for Pfizer.  

See the attached press release.  Also related to a recent NYT article: https://www.nytimes.com/interactive/2021/03/03/science/vaccine-efficacy-coronavirus.html?smid=em-share

Link to the paper (free for the next 50 days):

https://authors.elsevier.com/a/1clmj3BcJQ6%7EIk

*Frank, K.A., *Lin, Q., *Maroulis, S. J.,, and *Mueller, A. S., Xu, R., Rosenberg, J.M., Hayter, C. S., Mahmoud, R.A., Kolak, M., Dietz, T., Zhang, L. (on-line first ). “Hypothetical case replacement can be used to quantify the robustness of trial results.” Journal of Clinical Epidemiology. *equal first authors, listed alphabetically. DOI:https://doi.org/10.1016/j.jclinepi.2021.01.025

app is at: http://konfound-it.com

Ken