Boolean versus ranked querying for biomedical systematic reviews

Table 4 Retrieval effectiveness when metadata is tagged explicitly for ranked querying.

Target	Method	RBP99	P@1,000	R@1,000	P@10,000	R@10,000
Tier 0	A	0.184^†	0.135	0.159	0.051^†	0.483
	B	0.115^‡	0.100^‡	0.101^†	0.044	0.402^†
Tier 1	A	0.079^†	0.049^†	0.343	0.011	0.752^†
	B	0.036^‡	0.029^‡	0.203^‡	0.009^†	0.625^‡
Tier 2	A	0.041^†	0.022^†	0.442	0.005	0.856^‡
	B	0.014^‡	0.012^‡	0.259^†	0.004^†	0.689^†

In Method A, metadata is indexed separately; Method B searches metadata separately, but also includes it as part of the abstract text. All results are shown for searching from MEDLINE to the Target level indicated. †, ‡ indicate paired t-test with 95 and 98 percent confidence levels respectively (over baseline of TRC queries).

ISSN: 1472-6947