About
 Introduction
 Search Concepts
 PubMed
 Ovid
spacer.gif (43 bytes) spacer.gif (43 bytes)

backspacer.gif (43 bytes)next

Backspacer.gif (43 bytes)Next
spacer.gif (43 bytes)
backspacer.gif (43 bytes)next
Backspacer.gif (43 bytes)Next

 spacer.gif (43 bytes)

 spacer.gif (43 bytes)sovid.gif (4939 bytes) backspacer.gif (43 bytes)next

3. Ovid - The Systematic Search

There is only one step involved in running the systematic search, and that is to press the "Run Saved Search" option to take you to your personal saved searches. You select the relevant search (in this case, one of your Therapy searches) and press "Run Search". The search will run and usually you will automatically return to the Main Search Page (if not, click on the 'Main Search Page button to do so).

If you have not saved any of the systematic searches, for your convenience I have listed the Haynes searches below.

Table 1. Systematic Searches
Category
sens/spec		 BMA OVID MedlinePlus search string Results
Therapy sensitivity
99%/74%		 randomized controlled trial.pt. or dt.fs. or tu.fs. or random$.tw. 1205397
Therapy specificity
57%/97%		 (double and blind$).tw. or placebo.tw. 82076
Diagnosis sensitivity
92%/73%		 exp "sensitivity and specificity"/ or sensitivity.tw. or specificity.tw. or di.xs. or du.fs. 2425797
Diagnosis specificity
55%/98%		 exp "sensitivity and specificity"/ or (predictive and value$).tw. 101585
Aetiology sensitivity
82%/70%		 exp cohort studies/ or exp risk/ or (odds and ratio$).tw. or (relative and risk).tw. or (case and control$).tw. 597971
Aetiology specificity
40%/98%		 case-control studies/ or cohort studies/ 54668
Prognosis sensitivity
92%/73%		 incidence/ or exp mortality/ or follow-up studies/ or mo.fs. or prognos$.tw. or predict$.tw. or course.tw. 909271
Prognosis specificity
49%/97%		 prognosis/ or survival analysis/ 175832
Sensitivities and specificities quoted from Haynes RB, Wilczynski N, McKibbon KA, Walker CJ, Sinclair JC. Developing optimal search strategies for detecting clinically sound studies in MEDLINE. J Am Med Inform Assoc 1994 Nov-Dec; 1(6): 447-58.


Table 2. Other Useful Searches
Search OVID Comment
REVIEWS (systematic adj review$.tw.) or (data adj synthesis.tw.) or (published adj studies.ab.) or (data adj extraction.ab.) or meta-analysis/ or meta-analysis.ti. Mid-range sensitivity/specificity search as recommended by NHS CRD. Note that PubMed has no ADJ operator. See also article in ACP for other search strategies for reviews.
IRRELEVANT ((comment or letter or editorial).pt.) or (animal/ not (animal/ and human/)) Exclude irrelevant hits such as animal studies or letters by combining with other search using the NOT operator. e.g. REVIEWS NOT IRRELEVANT
GUIDELINES exp guidelines/ or guideline.pt. or practice guideline.pt. or health planning guidelines/ or (guideline$ or recommend$ or consensus).tw. This search is based on recommendation from the Canadian Centres for Health Evidence


Combining the Subject and Systematic Searches

Your subject search is now probably not visible as Ovid only shows the last four search steps. Press the explode button on the right hand side of the search table to see all of your search steps. Combine your subject search final line with your systematic search final line using syntax such as "1 and 5" in the search box. Unlike PubMed you do not use the # symbol before the number, and upper (AND) or lower (and) case Boolean operators are allowed. Press "Perform Search" to view the final result.

Tidying Up

At this stage you can tidy up your search. I often run my 'Irrelevant' search and combine it using 'NOT' to exclude letters, comments and editorials, and animal studies. In addition, you can set the date range, and specify English language if you wish.

Summary

The above tutorial has taken some time to work through. At normal speed you can accomplish the search in a couple of minutes. The preliminary search strategy is to: -

  1. Type in search string and map to MeSH, using Explode, but not Focus, and including the .mp option. Use any additional textwords, combining using Boolean OR with the MeSH search. This is the most sensitive subject search.
  2. Execute the systematic search.
  3. Combine the subject search and the systematic search using Boolean AND.
  4. If you wish, add limits such as language and date.

If you find too many results you can increase the specificity of the subject search by using Focus, and by selecting only some of the floating sub-headings. You can also use a more specific systematic search.

The next section covers features of the Ovid interface such as the Toolbar at the top of the main search page, and useful command line syntax.