Table 2 shows correlation coefficients between pairs of the 7 subjective measures, calculated using the placebo-adjusted adaptive response. Table 3 shows the results of the principal component analysis performed using these measures. The first principal component (PC1) for the placebo-adjusted adaptive response had an eigenvalue = 2.52, and accounted for ≥ 36% of the observed total variance. The variables with the highest correlation coefficients, Enjoyment, Intoxication, Stimulation, and Number of Drinks were the strongest contributors to PC1. The second principal component (PC2) had an eigenvalue = 1.2, but accounted for less than 18% of the variability, and was not used in subsequent analyses.
