Table 3. PCA dimensionality reduction metrics.

Median absolute error (MAE) of the linear inverse transformation from the data projected on the principal components to the original space of taxon abundances. Q_loc and Q_glob metrics denote preservation of the local and global data structure (see the text for details). Notation as in Table 2.

Dataset	Tax	MAE	Q loc	Q glob
AGP	O	0.061	0.90	0.99
	F	0.041	0.96	0.99
	G	0.050	0.95	0.99
HMP	O	0.036	0.91	0.99
	F	0.044	0.92	0.98
	G	0.058	0.92	0.99