Extract patient-level data from a Kaplan-Meier plot

I made a video with step-by-step instructions for extracting (approximate) patient-level data from a Kaplan-Meier curve. It’s a useful thing to be able to do, and while there are plenty of references already (see below) I thought perhaps a full guide using completely free software was missing.


Guyot, P., Ades, A., Ouwens, M.J. et al. Enhanced secondary analysis of survival data: reconstructing the data from published Kaplan-Meier survival curves. BMC Med Res Methodol 12, 9 (2012). https://doi.org/10.1186/1471-2288-12-9

Wei, Y., & Royston, P. (2017). Reconstructing Time-to-event Data from Published Kaplan–Meier Curves. The Stata Journal, 17(4), 786–802. https://doi.org/10.1177/1536867X1801700402

Author: Ankit Rohatgi Title: WebPlotDigitizer Website: https://automeris.io/WebPlotDigitizer Version: 4.2 Date: April, 2019 E-Mail: Location: San Francisco, California, USA


Satagopan, Jaya M., Alexia Iasonos, and Joseph G. Kanik. “A reconstructed melanoma data set for evaluating differential treatment benefit according to biomarker subgroups.” Data in brief 12 (2017): 667-675. https://doi.org/10.1016/j.dib.2017.05.005

Dominic Magirr
Medical Statistician

Interested in the design, analysis and interpretation of clinical trials.