Table 9.

Performance decrease when removing features in terms of precision (P), recall (R) and F-measure (F)

Features	P (%)	R (%)	F (%)
All features	92.01	83.72	87.67
General linguistic features	86.62	58.02	69.49
Character features	87.78	80.44	83.95
Semantic features	87.12	80.66	83.77
Dictionary features	88.64	83.65	86.07
Contextual features	89.81	83.62	86.60
Case pattern features	91.02	82.97	86.81

All mentions in our test set were used in this study.