In light of these difficulties, we downloaded the same datasets from the PRIDE repository and systematically reanalyzed all of the data, using a standard search procedure-the Tide search engine followed by Percolator with PSM-level FDR control at 1%. We then filtered the PSMs to prevent any peptide sequence from appearing in more than one species. The resulting data set was used to evaluate Casanovo . Finally, because some of the single-species datasets are markedly larger than others, we produced a more balanced version of the dataset. Hence, we make publicly available both versions of this dataset: the peptide-disjoint dataset that can be used to avoid train/test leakage ("main"), and the reduced peptidedisjoint dataset if you want your analysis to run more quickly ("balanced"). In addition, we make available all of the intermediate files, for use in validating the benchmark.