Suppose a set of N articles
There are a set of N (N-1) / 2 sets of
TP: the same kind of articles have been assigned to the same cluster
TN: different types of articles are assigned to different clusters
FP: different types of articles are assigned to the same cluster
FN: the same class were assigned to different clusters article
The correct measure of the percentage of Rand Index
RI = （TP+TN）/（TP+FP+FN+TN）
Thus, FP = 40-20 = 20.
Similarly,
Accordingly, TN = 96-24 = 72.
|
|
Same cluster |
Different clusters |
| Same class |
TP=20 |
FN=24 |
| Different classes |
FP=20 |
TN=72 |
RI = (20 + 72) / (20 + 20 + 24 + 72) = 0.68
Precision=TP/(TP+FP)
Recall=TP/(TP+FN)
F1 = 2×Recall×Precision/(Recall+Precision)
Precision=20/40=0.5
Recall=20/44=0.455
F1 = (2 * 0.5 * 0.455) / (0.5 + 0.455) = 0.48