Table 2: Principal components analysis summary for the 14 ICD-9 medical claim categories.

Component % Common
Variance Explained*
Cumulative %
1 43.84% 43.84%
2 9.46% 53.30%
3 8.03% 61.33%

* These figures represent the extent to which the variance among the 14 ICD-9 categories can be explained by underlying factors. The most important underlying factor explains about 44% of the variance shared by these different disease categories, while the next most important factor explains only about 9.5%.