PCA can also be used to gain insight into the structure of the data set in two ways. First, the factor loadings can be used to plot the variables in the principal components space (this is the “Loading Plot”). And it is sometimes possible to see which variables are “close” to each other in the principal components space. Second, the principal component scores can be plotted for each observation (this is the “Score Plot”), and aberrant observations or small, unusual clusters might be noted.
