TABLE 4.

Pairwise distances between site‐specific covariance matrices

	Unharmonized	ComBat	CovBat
A,B	5.39	4.29	2.60 (2.59–2.90)
A,C	5.82	4.27	2.50 (2.49–2.76)
B,C	4.69	3.32	2.67 (2.65–3.18)

Note: Differences in covariance structure between sites are reported as the Frobenius distance between covariance matrices calculated across observations acquired on each site. Results from adjusting the number of PC scores ranging from those explaining 44–100% of variation are shown in parentheses as the minimum and maximum pairwise Frobenius norms across the range.