Table 6. Performance of different feature combinations using gold standard medical concepts.

	Explicit recognizer			Implicit recognizer			Micro	INC
No	P	R	F	P	R	F	F
Baseline	0.9168	0.7839	0.8452	0.9206	0.6919	0.7900	0.8320	/
DF1	0.9088	0.8296	0.8674	0.9224	0.7094	0.8020	0.8520	0.0200
DF1+DF2	0.9108	0.8439	0.8761	0.9299	0.7160	0.8091	0.8604	0.0284
DF1+DF2+CF	0.9234	0.8469	0.8835	0.9361	0.7248	0.8170	0.8678	0.0358
DF1+DF2+CF+WF1	0.9396	0.8667	0.9017	0.9463	0.7391	0.8300	0.8848	0.0528
DF1+DF2+CF+WF1+WF2	0.9451	0.8735	0.9079	0.9484	0.7415	0.8327	0.8901	0.0581
DF1+DF2+CF+WF1+WF2+WF3	0.9481	0.8776	0.9114	0.9505	0.7455	0.8356	0.8936	0.0616
DF1+DF2+CF+WF1+WF2+WF3+HF	0.9481	0.8776	0.9114	0.9686	0.7631	0.8537	0.8978	0.0658

*Inc is increment compared with baseline.