Transcript Effective Literature Searching Some frequently asked questions

Effective Literature Searching
Some frequently asked questions
Library & Archives Service
www.lshtm.ac.uk/library
I’ve never done any searching before,
where should I begin?
1
2
• Define your topic
• Choose the resources to search
3
You should work through the 5 steps of an effective literature
search. Working logically through these steps ensures your
• Choose
your
search and
terms
search
is focused,
systematic
effective.
4
The Library has produced a handbook taking you through each
step,
you can download
it at http://bit.ly/hCUzEq
• Compile
the strategy
and run the search
5
• Find the full text
These are the 5 steps. You’ll notice that it is not until step 4 that you actually run your search in a database.
Some people find this surprising, but it is important that you don’t miss out the 3 preparatory stages. If you
don’t spend some time planning first you will find it frustrating and difficult to retrieve material relevant to
your topic.
I have a rough idea of my topic, how can
I turn this into something I can search
on?
You need to work through step 1 of the literature search process:
defining your topic. The next few slides will take you through the
basics to achieve this, but this help sheet gives more detailed
information http://bit.ly/epHrbT.
Firstly, you must be very specific about what it is you want to
find. This may sound obvious, but you are going to be searching
a vast body of literature. There are over 20 million citations in the
PubMed database alone and only a small proportion of these will
be relevant to your topic. Unless you are very clear about what
you want, retrieving these relevant items will be extremely
difficult.
What do you want the literature to tell you?
Ask questions…
Question x4 by Mike Coghlan
http://www.flickr.com/photos/mikecogh/4256561918/
Reproduced under a Creative Commons Licence
Turning our topic into a question is helpful because it forces us to think about what it is we really want to
find. It is important that this question is focused. “How can maternity services be best delivered?” is too
vague and ill-defined for an effective literature search. Think about how many potential papers this could
retrieve. “Which are the most effective ways to deliver maternity services to rural populations in lowincome countries” is much more appropriate. In this case we have defined our topic by thinking about a
specific population and geographical setting.
Which are the most effective ways to deliver maternity
services to rural populations in low-income countries?
Once you have developed a question you must identify the key concepts within it. Which concepts must
every paper that you find address in order for it to be relevant to you? We will need to use these concepts
when we come up with our search terms.
I have highlighted the concepts that make up my question in red. Everything I find must be about maternity
services, rural populations and low-income countries. If any of these concepts are not represented in a
paper then it will not be relevant to me and I don’t want to find it.
Which databases should I search?
PubMed/Medline
Embase
Biomedicine and clinical
medicine
Biomedical and clinical
medicine
Global Health
International public health
This is step 2 of the literature search process. The databases you
choose depend very much on the search topic. Each database
covers a different topic or type of information and you must
Africa-Wide
choose the ones Cochrane
that are mostLibrary
appropriate for your
search
CINAHL
Information
question.
Information from or about
Africa
Healthcare interventions
Popline
Web of Science
ELDIS
Reproductive and sexual
health
All academic disciplines,
good for social sciences
Grey literature related to
development issues
Nursing and allied health
LSHTM database subscriptions are grouped by topic on our webpages http://bit.ly/MlnRqz. You may be prompted to log-in with
your Moodle username and password (begins with lon).
These are some popular databases used at the School. More information is available in this guide
http://bit.ly/dYnuFT. Find our complete database listing at http://bit.ly/MlnRqz.
How do I identify appropriate
search terms?
Choosing your search terms is step 3 of the literature search
process. We will need to refer back to the concepts we came up
with at step 1.
A database is not cognitive, and it especially can’t understand
nuances in language. If I search for maternity services the database
will not know I also want to find papers that discuss maternity care
or maternal health services.
You need to think of all the ways each of your concepts could be
described in the title or abstract of a paper. Spend some time
generating this list of keywords, your results will only be as good as
what you put in.
Further information about indentifying search terms is available
http://bit.ly/egNdZl
Which are the most effective ways to deliver maternity services
to rural populations in low-income countries?
Maternity Services
• Maternal health
service(s)
• Maternal healthcare
• Maternal health care
• Maternal service(s)
• Maternity care
• Maternity service(s)
• Postpartum
care/service(s)
• Postnatal care/service(s)
• Prenatal care/service(s)
• Antenatal care/service(s)
Rural populations
•
•
•
•
•
•
Rural community/ties
Rural population(s)
Remote population(s)
Remote community/ties
Non-urban
Villages
Low income countries
• Developing
country/countries
• Developing nation(s)
• Developing world
• Low resource setting
• LMIC(s)
• Africa(n)
• South East Asia(n)
• South America(n)
Here are the keywords I came up with for each of the concepts in my maternity services question. Notice
how I have considered different word endings such as plurals, the databases will not search for these
automatically. You should also make sure you account for differences in UK and US spellings or terminology,
and include the full name of any abbreviations.
What are subject headings?
You may also hear subject headings referred to as MeSH terms or thesaurus
terms. When we search by subject heading we are not searching the terms the
author has used in the title or the abstract, we are searching index terms that
have been applied to each article to show what it is about.
They work in much the same way as the index of a book. When we look up HIV
in an index it tells us all the pages which have content about HIV. In a similar
way, using the subject heading HIV will bring us all the items in a database
about HIV – whether they have used the term HIV, HIV-1, HIV-2, human
immunodeficiency virus or something else to describe
that
concept.from the
This is
a record
Medline database. In the red
Not every database uses subject headings, and those that do each use a
box are
indexkeywords
terms that are
different set of index terms. A comprehensive search
will the
use both
applied
to this record to show
and subject headings. A fuller explanation is available
http://bit.ly/egNdZl
what the paper is about. It is
these terms that you are
searching when you search by
subject heading.
How do I combine my search terms together?
We are now up to step 4 of the search process, compiling the
search and running it in a database. This step is more
completely explained here http://bit.ly/fJckU7.
We have to input our search terms in a way that the databases
understand so that they run the search in the way we want
them to.
Most importantly, we have to use Boolean operators to join our
terms – AND & OR.
OR
Search
1
AND
Search
2
OR means either – we join terms with OR when
we want to find any of them. OR finds articles
with one or more of our terms, so all of the blue
areas in the diagram. We use OR to join our
synonyms for the same concept – we want to find
anything that discusses either maternity care OR
maternal healthcare.
AND means both – if you join terms with AND
you will only find items in which those terms
appear together. AND finds articles with all of
our terms, so only the blue area of the diagram.
We use AND to combine our searches for
different concepts – we want to find papers
discussing both maternity services AND rural
communities.
( ______ OR ______ ) AND ( _____ OR _____ OR _____ )
When we use AND & OR together in the same search line we need to use brackets to show the order in
which we want our terms combined. They work in the same way as brackets in algebra, breaking up
discrete and separate sections of the search.
You can run your search as one long search string, using brackets
to separate the concepts…
("maternity services" OR "maternal
health services" OR "postnatal care" OR
"postpartum care") AND ("rural
populations" OR "remote populations"
OR "rural communities" OR "remote
communities" OR non-urban OR villages)
AND ("developing country” OR "low
income country" OR africa OR "south
america" OR "south east asia")
Or in many databases you can search for each concept separately,
and then combine the individual searches together with AND at
the end.
1.
2.
3.
4.
(matern* OR postnatal OR postpartum OR prenatal) and (care OR
service*)
rural communit* OR remote communit* OR rural population* OR
remote population* OR village* OR non-urban
developing countr* OR low-income OR africa* OR south america*
OR south east asia*
1 AND 2 AND 3
I have used truncation in this search (*). Adding the truncation symbol to the root of a word will find all
the possible word endings e.g. matern* will find both maternal and maternity. You can find more tricks
like this to improve your search here http://bit.ly/fJckU7
For the most comprehensive search your strategy should combine both
keyword and subject heading searching. The structure will look something like
this:
1. Concept
(matern*
OR postnatal
OR postpartum OR prenatal) and (care OR
1.
1 keyword
search
service*)
2. Concept 1 subject heading search
2. exp Maternal Health Services/
3.
1 OR 2
3. 1 OR 2
4.
2 keyword
4. Concept
rural communit*
ORsearch
remote communit* OR rural population* OR
5. Concept
subject heading
search
remote2population*
OR village*
OR non-urban
5. 4 OR
exp5Rural Health Services/ OR Rural Population/
6.
6. Concept
5 OR 6 3 keyword search
7.
7. Concept
developing
world OR
africa*search
OR south america* OR south east asia*
8.
3 subject
heading
8. exp Developing Countries/
9. 7 OR 8
9. 7 OR 8
10.3 AND 6 AND 9
10. 3 AND 6 AND 9
Why has my search not found what I need?
Don’t expect to put together a perfect search strategy first
time. Searching is an iterative process and it often takes a
couple of revisions before you have a strategy that is
effective at finding what you want.
First, look at the results you have retrieved. Most databases
will highlight your search terms in the results so you can see
why a particular item was returned. Use this to start your
thinking about how the strategy could be improved.
Why has my search not found what I need?
Problem 1 – I can’t find any papers
Is the scope of your search too narrow? In this search, the strategy is very specific in that it only wants
Have
you
checked
your
spelling
and usethe
of focus
syntax?
sure you have
not misspelt
crucial
keyword,
to find
papers
about
Brazil.
Expanding
to Make
find potentially
relevant
material afrom
other
South
and
you have
used Boolean
operators,
truncation
American
countries
would retrieve
more
results. etc correctly.
Are
you
searching
relevant
database?
Different
databases
contain
information, does
Have
you
includedthe
all most
relevant
keywords
and subject
headings?
This
searchdifferent
has not identified
the
one youfor
areeach
using
your topicThis
area?
The that
search
aboveusing
is from
Medline, but
perhaps
Global
synonyms
ofcover
the concepts.
means
papers
terminology
other
than that
Health
andinPopline
would
results
assearch
they focus
onexclude
international
public
health
included
the search
arefind
not more
retrieved.
The
would
anything
where
the and
author talks
reproductive
health
respectively.or “vertical transmission”. You can use the terminology found in
about “maternal
transmission”
papers you have already identified to add to your list of terms.
Why has my search not found what I need?
Problem 2 – I have too many irrelevant papers
Check your search terms, are they specific to the information you want to find? Often the same word
can be used in many different contexts. In this search, nursing has been used as a synonmyn for breastfeeding which returned many irrelevant results about the nursing profession. In cases like these you
will have to decide whether the term can be omitted from the search without loosing crucial papers.
Look out for where you have used very general terms in your search and replace these with what it is
you really want to find. Participation is not a great search term as it could mean anything. Terms like
“patient participation” or “community participation” are more specific and therefore more effective.
I’ve found some useful papers,
now how do I get the full text?
This is step 5 of the literature search process, finding the
full text.
There are 4 ways you can do this
1. Using the SFX@LSHTM button from within the
database. Find out how this works here
http://bit.ly/hQc74Y
2. LSHTM Library catalogue http://bit.ly/fIAuBg
3. Using another Library – we can advise on schemes
such as SCONUL Access (http://bit.ly/IZGL5) and
HINARI (http://bit.ly/19DiQF)
4. Request the material via our Document Delivery
service http://bit.ly/eA8MJK
How can I best manage my
references?
Mendeley
IT Services
supports reference management
(http://bit.ly/eIhYsI)
software, rather than the Library. They have
written guides to two freely available, webbased resources.
You can import references from most databases
into these resources. The guides will take you
through this.
Zotero (http://bit.ly/hEULXv)
I still have some questions...
• There is lots more information available on our web-pages
http://bit.ly/dKcW3C, including resources for more
advanced searching.
• Post a question to the Library Support Conferences on
Moodle
• Contact us by email [email protected]