Table 1

 Sources of studies for the review

SourceAll relevant studiesStudies finally included
Number% Of totalNumber% Of total
First line health databases
Found in CINAHL, Cochrane Library (CDSR and CCTR), Embase, Medline, PreMedline, or PsycInfo 4 6 3 14
First line science databases
Found in ASSIA, IBSS, Sociological Abstracts, or Web of Science (SCI or SSCI)73
Found in reference list of another document indexed in one of these databases1
First line science databases (total) 8 12 3 14
Other specialist databases
Found in Dissertation Abstracts, Geobase, HELMIS, HMIC, Index to Theses, PapersFirst, REGARD, or SportDiscus 8 12 2 9
Transport database
Found in Transport307
Found in reference list of another document indexed in Transport32
Transport database (total) 33 48 9 41
Purposive search of web sites 9 13 2 9
Reviewers’ own collections
Experts’ recommendations
Found by chance
Found in a book or set of conference proceedings ordered for another document62
Found by unstructured web browsing11
Found by chance (total) 7 10 3 14
Total 69 22