Classification accuracy and speed comparison of variants of Kraken for three simulated metagenomes. For each metagenome, genus precision and sensitivity are shown for five classifiers, and speed is shown for Kraken, along with a reduced memory version of Kraken (MiniKraken), quick execution versions of both (Kraken-Q and MiniKraken-Q), and Kraken run with a database containing draft and completed microbial genomes from GenBank (Kraken-GB). Results shown are for the same metagenomes used in Figure 2. Note that the scales of the axes differ from Figure 2, as the precision and speed of Kraken (and its variants) exceed that of the other classifiers used. (a) HiSeq metagenome. (b) MiSeq metagenome. (c) simBA-5 metagenome.