Automatic complaint classification system using classifier ensembles

Sambat Online is an online complaint system run by the city government of Malang, Indonesia. Because most citizens do not know to which work units (Satuan Kerja Pemerintah Daerah [SKPDs]) their complaints should be sent, the system administrator must manually sort and classify all of the incoming complaints with respect to the appropriate SKPDs. This study empirically evaluated the application of an automated system to replace the manual classification process. The experiments, which used Sambat Online data, involved five individual classification algorithms- Naïve Bayes, Maximum Entropy, K-Nearest Neighbors, Random Forest, and Support Vector Machines-and two ensemble strategies-hard voting and soft voting. The results show that the Multinomial Naïve Bayes classifier achieved the best performance, an 80.7% accuracy value, of the five individual classifiers. The results also indicate that generally all of the ensemble methods performed better than the individual classifiers. Almost all of them had the same accuracy level of 81.2%. In addition, the soft voting strategy had slightly higher accuracy than the hard one when all five classifiers were used. However, when the three best classifier combinations were used, both had the same level of accuracy.