Table 1.

Performance of keyword search using unigrams, bigrams, and a combination of both

	Precision	Recall	F1 score
Unigrams	0.043 (±0.02)	0.927 (±0.04)	0.081 (±0.03)
Bigrams	0.429 (±0.06)	0.635 (±0.04)	0.512 (±0.05)
Unigrams + bigrams	0.047 (±0.00)	0.895 (±0.04)	0.089 (±0.00)

Note: Results are reported as mean (±95% confidence intervals) obtained from 10-fold cross-validation on the training set