There are many evaluation measures available like entropy, recall, precision, F-measure, silhouette co-efficient, purity, inverse purity for improving cluster‘s accuracy, efficiency and result.
1. Recall=A/(A+B), where A is the true positive, B is the false negative
Pecision = A/(A+C), where C is the false positive
F-measure=2*Precision*recall/ (precision+recall)
2. Purity, Silhouette co-efficient:
原文：http://www.cnblogs.com/kellytran/p/5986941.html