Google Scholar as replacement for systematic literature searches: good relative recall and precision are not enough

Table 2 Combined precision of the Cochrane review searches as retrieved from the Cochrane reviews

Review	References found^*	References included^**	Precision [%]
Arrol [21]	--	14	--
Sinclair [22]	517	49	9.4
McQueen [23]	636	14	2.2
Bar-On [24]	246	20	8.1
Bohlius [25]	5546 (+ 575)	48	0.9
Boehm [26]	675	51	7.6
Guimarães [27]	775	11	1.4
Verbeek [28]	2491	24	1.0
Yip [29]	--	17	--
Okebe [30]	“large number“	70	--
Ipser [31]	1395 (+ 655 + 193)	22	1.6
Sultan [32]	--	11	--
Oduyebo [33]	701	24	3.4
Mestre [34]	102	21	20.6

For more details esp. on the number of searched databases see Additional file 2.
^*: Usually not specified if doublets are excluded. In brackets “ongoing“ studies which were not further processed.
^**: “citations included“ is the number of single references of included studies with one major reference per study.

ISSN: 1471-2288