Addendum to: Nature Published online 01 January 2020

To assist with the replication of our results, we have expanded the Supplementary Methods of our Article to provide more detail on how our deep learning system was trained. This includes additional optimization hyperparameters, as well as a more exhaustive description of the data augmentation strategy. Revised Supplementary Methods are presented in the Supplementary Information to this Addendum. Please also see the accompanying Matters Arising Comment (Haibe-Kains et al., and Reply (McKinney et al.,

 In addition, the middle initial of author Greg Corrado should be ‘S’ rather than ‘C’. This error has been corrected online.

Supplementary Information is available in the online version of this Amendment.