Table 4. Tuning of the re-ranking experiments for the Question-Answering task.

Collection	Re-ranking	Queries answered	P0	R5
MEDLINE	Baseline	23/23	0.53	0.34
	Cost (based on Swiss Compendium)	23/23	0.62	0.38
	Resistance (based on data from 2006)	23/23	0.56	0.37
	Adverse Drug Reaction	23/23	0.50	0.32
	Combination	23/23	0.60	0.33
PubMed Central	Baseline	23/23	0.44	0.20
	Cost (based on HUG cost list)	23/23	0.48	0.34
	Resistance (based on data from 2006)	23/23	0.44	0.32
	Adverse Drug Reaction	23/23	0.46	0.25
	Combination	23/23	0.51	0.27
Cochrane Library	Baseline	22/23	0.30	0.20
	Cost (based on HUG cost list)	22/23	0.46	0.30
	Resistance (based on data from 2006)	22/23	0.33	0.30
	Adverse Drug Reaction	22/23	0.31	0.19
	Combination	22/23	0.43	0.22