|
Reasons why studies were missed by electronic search and handsearch |
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| Category |
Reason |
Studies citing reason (n = 42) |
|
|
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| Electronic Resources |
||
| Indexing |
||
| Inadequate indexing in general |
16[3,27,29,32–44] |
|
| Journal not indexed in resource |
8[3,13,20,27,35,40,45,46] |
|
| Not indexed with proper methodologic terms |
9[21,26,28,29,32,36,42,47,48] |
|
| Not indexed as RCT/CCT |
7[35,37,49–53] |
|
| Not indexed for any of the methodologic terms used by searchers |
2[21,54] |
|
| Database does not contain relevant index terms |
2[17,50] |
|
| Not indexed with any of the subheadings used in searches |
1[21] |
|
| Search Strategy |
||
| Insufficient or restricted search strategy |
6[27,32,35,55–57] |
|
| Reporting |
||
| Keywords or methodology not reported by author |
9[13,19,29,34,41,48,53,58,59] |
|
| Database |
||
| Issue(s) omitted from resource |
4[3,26,56,60] |
|
| Time lag in updating resource |
2[60,61] |
|
| Article(s) omitted or missing from resource |
6[3,29,36,50,51,56] |
|
| Journal |
||
| Published before database was created or beyond coverage years of database |
2[56,60] |
|
| Other |
||
| Unknown reason |
6[26,38,38,54,60,62] |
|
| Published as abstracts, books, book reviews, brief reports, letters, proceedings, supplements, etc. |
9[20,26,38,38,49,51,56,63] |
|
| • Wrong abstract assigned to reference[36] • Journals do not encourage authors to explicitly report methodology[37] • Length and complexity of search is limited using search engines[64] • Ongoing or recently finished studies[64] • Found through references[20] • Missed most Japanese reports[65] • Some personal communication did not get responses; organizations and people must be willing to supply trial information[18] • Not all abstracts are published in full[50] • Authors misspelled gingko[39] • Many RCTs are not identifiable in database[66] |
||
| Handsearch |
||
| Handsearchers not trained properly |
2[57,67] |
|
| Methodologic terms "hidden" in article |
1[26] |
|
| Searcher fatigue, boredom |
1[26] |
|
| Journal not handsearched |
2[35,42] |
|
| Article not an RCT or CCT |
1[54] |
|
| Other |
||
| Different topic than what handsearchers were looking for |
1[42] |
|
Crumley et al. BMC Medical Research Methodology 2005 5:24 doi:10.1186/1471-2288-5-24 |
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