For our TF-PCA components, we first wanted to confirm that the decompositions were stable across our different cohorts of subjects (i.e. across males and females in the 11 and 17 year old cohorts; see Figure 2 which illustrates the ERP and the 5 TF components extracted from the TF-PCA decomposition). We assessed stability of the PCA solution across the independent cohorts of subjects by conducting the TF-PCA decomposition separately for each, and then computing Tucker's congruence coefficients (which measure the similarity of two factorial configurations by ascertaining the degree to which the magnitude of loadings on the two factors have a similar pattern; values in excess of .90 indicate high congruence). Congruence coefficients between matching components were uniformly high, ranging from .93 to .99 across age cohorts and from .93 to .95 across gender cohorts, indicating that the TF-PCA decompositions had highly similar patterns.
