Our latest digest is a special edition focused for the most part on Embase. As many of you will be aware, Cochrane has been engaged in the Embase Project for the last couple of years, an attempt to find all the RCTs and CCTs on that database and make sure that they are available in CENTRAL. Have a look at the CENTRAL creation pages to find out more about how that works, and find out more about the Embase Project here. This page will also show you where the project is up to in terms of records screened.
Embase Special Edition
Embase user guides and other useful documents
Ovid users might find this guide helpful, and you can find out more about which journals are indexed in Embase here.
If you have access to Embase.com, a quick start guide is available, and there is a more comprehensive guide here.
Embase have also made available their complete indexing policy.
There is some information here for Ovid users on field codes, and users of Embase.com can find field codes (called search codes) in this document.
You can find a comparison between the two sets of search syntax on this page on the TSC Portal.
Embase RCT filter from the Embase Project
Part of the Embase Project was to develop a search filter to identify the trials, and Julie Glanville has worked on this part of the project. You might be interested in using this filter in your own Embase searches.
The Embase Project uses two search strategies to identify RCTs for CENTRAL: Set 1 is identified using the Emtree headings Randomized Controlled Trial or Controlled Clinical Trial, these records have a direct feed into CENTRAL and are not screened by the crowd. Set 2 is identified by a search string shown on the CENTRAL creation pages of the Cochrane Library website. These combined sets form a highly sensitive search strategy which identifies many non-RCTs. The Embase Project then uses crowd sourcing for secondary screening to ensure that the records being sent to CENTRAL are true RCTs.
When searching for reviews, TSCs may prefer a greater level of specificity and one pragmatic suggestion from the Embase project team would be to leave out the term ‘human experiment’ at line 18.
The strategy has been developed using the OVID platform, and kindly translated for Embase.com by Ian Crowlesmith of Elsevier in October 2015. Note that lines 13 and 15 are identified by Ian as similar but not identical to the OVID search phrases.
OVID Embase:
1. Randomized controlled trial/
2. Controlled clinical study/
3. Random$.ti,ab.
4. randomization/
5. intermethod comparison/
6. placebo.ti,ab.
7. (compare or compared or comparison).ti.
8. ((evaluated or evaluate or evaluating or assessed or assess) and (compare or compared or comparing or comparison)).ab.
9. (open adj label).ti,ab.
10. ((double or single or doubly or singly) adj (blind or blinded or blindly)).ti,ab.
11. double blind procedure/
12. parallel group$1.ti,ab.
13. (crossover or cross over).ti,ab.
14. ((assign$ or match or matched or allocation) adj5 (alternate or group$1 or intervention$1 or patient$1 or subject$1 or participant$1)).ti,ab.
15. (assigned or allocated).ti,ab.
16. (controlled adj7 (study or design or trial)).ti,ab.
17. (volunteer or volunteers).ti,ab.
18. human experiment/
19. trial.ti.
20. or/1-19
Embase.com
1. "randomized controlled trial"/de
2. "controlled clinical study"/de
3. random*:ti,ab
4. randomization/de
5. "intermethod comparison"/de
6. placebo:ti,ab
7. (compare OR compared OR comparison):ti
8. ((evaluated OR evaluate OR evaluating OR assessed OR assess) AND (compare OR compared OR comparing OR comparison)):ab
9. (open NEAR/1 label):ti,ab
10. ((double OR single OR doubly OR singly) NEAR/1 (blind OR blinded OR blindly)):ti,ab
11. "double blind procedure"/de
12. (parallel NEXT/1 group*):ti,ab
13. (crossover OR "cross over"):ti,ab
14. ((assign* OR match OR matched OR allocation) NEAR/5 (alternate OR group* OR intervention* OR patient* OR subject* OR participant*)):ti,ab
15. (assigned or allocated):ti,ab
16. (controlled NEAR/7 (study OR design OR trial)):ti,ab
17. (volunteer OR volunteers):ti,ab
18. trial:ti
19. "human experiment"/de
20. #1 OR #2 OR #3 OR #4 OR #5 OR #6 OR #7 OR #8 OR #9 OR #10 OR #11 OR #12 OR #13 OR #14 OR #15 OR #16 OR #17 OR #18 OR #19
A word about Scope notes for Embase in Ovid…
Ovid users may be frustrated by the fact that there appear to be no scope notes available for Emtree. We asked Elsevier about this and they told us that they have no control over scope notes in Ovid or how they are displayed. However, we have discovered that you can use the drop down menu in Embase Ovid to find scope note information, as in the picture below…
Note that the only indexing terms in Embase which have scope notes are check tags and subheadings. This helpful document contains all the Embase indexing information you need, with scope notes for check tags in Appendix 2 and scope notes for subheadings in Appendix 3.
Does the Embase Project mean I no longer have to search Embase separately for trials?
TSC Support are cautious about answering yes to this question at the moment. We’re hoping to do some validation work to see whether separate searches of Embase are still necessary; and we encourage all TSCs to have a go at similar validation work in their scope. However, any records in Embase indexed with the randomized controlled trial / controlled clinical trial Emtree term are automatically fed into CENTRAL every 4 weeks, so provided you are also searching CENTRAL, you could safely consider excluding these records in your Embase searches, up to the last 4 weeks of your search.
Thanks to Anna Noel-Storr, Julie Glanville, Ian Crowlesmith and Sherry Winter for their help with the information on Embase in this digest.
HarmoniSR guidance now available!
Find out how core fields in references and studies should appear in the CRS
As you may have seen, HarmoniSR guidance on core fields for reference and study records is now available. The old TSC Guide to Specialised Registers has now been retired and the HarmoniSR documents should now be used instead. Visit the TSC portal (Archie login required) to see the final report, the field guide for references and the field guide for studies. If you have any questions about the guidance, contact us! tsc-support@cochrane.org.
Contact us...
Don't forget, previous editions of the TSC Support Team digest are available on the TSC Portal (Archie login required)
Contact the TSC Support Team for help with any TSC related issue (including CRS technical support): tsc-support@cochrane.org
The TSC Support Team:
Liz Doney I Sam Faulkner I Ruth Foxlee
Anne Littlewood I Doug Salzwedel
