Hi Michael and everyone,
I really find this thread fascinating because I do a lot of searching
without the assistance of librarian/ information specialist. Of course it
helps to have expert input at many times, especially on small or internally
funded projects, that luxury is not an option. Therefore a lot of weight is
put on 'proven strategies'. Even these seem to be fluctuating from time to
time and we will just have to chose the best one we can find at any given
time.
As for the term meta-analysis vs. systematic review, just from experience
and looking at a million or so papers over the years, we tend to see them as
one, but in fact they are two separate entities. A systematic review may
contain have a meta-analysis and a meta-analysis may be built on the result
of a systematic review. Example:
Systematic review only: A systematic review where the evidence found in
sparse (e.g. only one included study) or heterogeneous and the authors
decide that synthesising the evidence is not practical. We would still want
these in our search strategy.
Meta-analysis only: The intentional pooling of similar trials produced by
the same team (or sponsored by the same pharmaceutical company) but with no
search for other studies or inclusion of other similar studies into the
analysis. We don't want these because they are not systematic reviews.
In my humble opinion, I believe that all true systematic reviews should
clearly state the words "systematic review" in their title/abstract. If it
was a systematic review and meta-analysis, then they should say "systematic
review and meta-analysis." The PRISMA statement asks authors to declare the
title the "report as a systematic review, meta-analysis, or both." Until
guidelines like these are enforced it will always be difficult to
electronically weed out the false positives (e.g. meta-analysis of selected
publications).
Best wishes,
Ahmed
_______________________________________
Ahmed M. Abou-Setta, MD, PhD
Post-doctoral Fellow/ Project Co-ordinator,
University of Alberta Evidence-Based Practice Center (UA-EPC)
Alberta Research Centre for Health Evidence (ARCHE)
University of Alberta (Canada)
Principal Evidence-based Medicine Consultant, PharmArchitecture Limited (UK)
Member, Editorial Advisory Board, The Open Medical Devices Journal
Member, Geneva Foundation for Medical Education & Research
Member, Menstrual Disorders & Subfertility Subgroup, Cochrane Collaboration
Aberhart Centre One, Room 8412
11402 University Avenue
Edmonton, Alberta
CANADA T6G 2J3
Tel: (780) 492-6248
Fax: (780) 407-6435
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Website: http://www.ualberta.ca/ARCHE/
-----Original Message-----
From: Evidence based health (EBH)
[mailto:[log in to unmask]] On Behalf Of Michael Power
Sent: July 14, 2010 10:03 AM
To: [log in to unmask]
Subject: Re: The new PubMed Clinical Queries Interface
Thanks Helena
The "MA as topic" back is back in my strategy for SRs as a result of your
explanation!
Unfortunately it does not compensate for bad indexing by Medline, or for
authors who call their article a systematic review/meta-analysis, when it is
plainly unsystematic. That's why we need people to apply some intelligence
and experience to searching and filtering.
We do have a filter for searching for guidelines, which was developed after
a lot of careful searching for and experimenting with different filters.
But, I do not use it because it does not work very well. This is perhaps not
surprising, as the indexing is very poor. For example, guidelines such as
those developed by NICE are not indexed by Medline - except indirectly when
a summary is published in a journal.
Our information specialists have just gone home, so you will have to wait
until tomorrow before I can send it to you. Because the filter is so poor,
our information specialists supplement the automated search for guidelines
with quite a detailed strategy for human searching and filtering of a number
of bibliographic databases and guideline repositories.
If anyone has a better Medline search filter than ours, we would of course
be delighted to prove yours superior.
Best wishes
Michael
-----Original Message-----
From: Vonville, Helena M [mailto:[log in to unmask]]
Sent: 14 July 2010 15:51
To: Michael Power
Subject: RE: The new PubMed Clinical Queries Interface
Probably the MA as topic is probably overkill, especially for a quick and
dirty search. However, I often work with students who are trying to develop
topics for their theses or dissertations. One of the benefits of using that
term is that you pick up comments and analyses from other authors that refer
back to the original SR/MA. Sometimes these comments serve as a stepping
off point for students so the overkill approach tends to work well for them.
And they appreciate my thoroughness which then encourages them to be as
thorough as possible.
As to your other comment-- I agree that a search for guidelines is critical.
In the course I co-teach, the students are strongly encouraged to look for
guidelines. During one of the lectures in our SR/MA course, the other
instructor goes into http://www.guidelines.gov and compares two or three
sets of guidelines for the same intervention/treatment/condition. This
provides the students with an opportunity to see the difference between
evidence-based guidelines and "because the experts say so" guidelines.
I probably should develop a filter for guidelines as well. Do you have one
that you use now?
Thanks so much for your comments.
Helena
Helena M. VonVille, MLS, MPH
Library Director
University of Texas School of Public Health Library
Houston, TX 77030
[log in to unmask]
713.500.9131 (office)
713.500.9125 (fax)
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