Advanced Literature Searching for Higher Degree Students of Psychology
Last update: 31 August 2011,
by Maureen Bell
When you embark on a higher degree the dreaded literature review will loom large in your early preparations. It can seem rather daunting, but if you follow a few simple rules you'll save time, and avoid a lot of confusion and frustration. Essentially you are dealing with two simple components - language, and logic. This page is to help you with both. Click here for printed notes
Language - trawling PubMed for terms and field codes
Compiling your lists of terms to search
Logic - constructing your search from the terms you've collected
PsycINFO - PsycINFO's language
Constructing your PsycINFO search
Other databases - moving on from PubMed or PsycINFO to Scopus (my favourite) and other sources
Systematic reviews - what they are, and some guidance for those undertaking one
Grey literature - essential searching for a systematic review
Language
One of the problems we all have is that we expect other people to call things by the same name that we do. Even if they don't, in normal conversation this is not a problem, as we rapidly process the alternatives as equivalents. So if I talk about sickness, and you talk about illness it really doesn't matter, as we still understand one another. Databases (with very few exceptions) don't work like this. Instead they search only the exact words we use (including misspellings!). This means that for comprehensive searching you need to provide them with as many possible alternatives as you can. Some of them (like PubMed and PsycINFO) even have their own indexing language, or thesaurus which needs to be considered as well. PubMed has a thesaurus called MeSH - which is simply an acronym for Medical Subject Headings.
We'll begin with PubMed, followed by PsycINFO, and the topic I've chosen is - cognitive therapy of ptsd.
Most postgraduate topics will have more components than this, but I'm using a simple example to demonstrate general principles.
Field Codes
When searching either PubMed or PsycINFO it's important to tell the database where to look for words - titles of articles, abstracts, or the indexing language of the database. To do this you need to use field codes.
PubMed has a wide range of field codes, but those you're most likely to use are:-
[mh] to search for Mesh terms
eg. cognitive therapy[mh]
[majr] to restrict your search to major indexing terms only
eg. cognitive therapy[majr]
[tiab] to search for words in titles and abstracts - this is essential for searching the most recent literature
eg. cognitive therap*[tiab]
[ta] to search for (Medline) journal title abbreviations
eg. J Clin Psychol[ta]
PsycINFO also has a wide range of field codes, but the codes you're most likely to use are:-
TI – Article title
AU – Author
AB - Abstract
DE – Exact Subject Heading
MJ - Word in Major Subject Heading
SO – Publication Name
Method
At first we won't worry about field codes - they'll come later. For a start just use your own words
- Open a Word document and set up a logic grid - you'll need a column for each concept.
Cognitive Therapy
|
PTSD
|
| cognitive therapy |
ptsd |
- Perform a simple search, using your own words - cognitive therapy AND ptsd
- Scroll through the results to see if there are any articles that look as if they're on your topic. What you'll need is one that includes
(PubMed - indexed for MEDLINE)
Very new material will be labelled either
(PubMed - as supplied by publisher)
or
(PubMed - in process)
and will not have indexing (MeSH) terms added to it.
- Once you have found a suitable article click on the title. This will display the article details, plus its abstract, and a link to enable you to view MeSH Terms.
- Clicking on the + sign will allow you to see the indexing (MeSH) terms which have been used to describe the content of the article.
Below is the indexing for the article:-
Are we ready for the big one? Lessons from a brief war that could apply to New Zealand primary health care services following a major disaster.
Parsonson BS, Rawls J.
J Prim Health Care. 2010 Sep 1;2(3):180-2.
Terms with an asterisk after them are Major terms, and represent the most important subject aspects of the article. Those without an asterisk are Minor terms, and represent less important aspects of the article's content. NOTE the asterisk here is NOT a wildcard.
Some of the indexing terms in this example have subheadings - for example /therapy.
WARNING When searching, using subheadings is very risky, as indexing at this level is rather variable. It's probably best to avoid them if you can.
You'll find a link to the MeSH Database in the drop down box from the Search box
- Look up cognitive therapy in MeSH
- Scroll down the MeSH page to look at the Entry Terms.
As new material in PubMed is not indexed, and as indexers, being human, are prone to error, or variation in the way they interpret the content of an article, words in titles and abstract need to be searched too. This list of Entry Terms provides suggestions for synonyms or alternative terms that might be used in the abstracts and titles of articles that don't have cognitive therapy as a Medical Subject Heading.
- Look up ptsd in MeSH
You'll see that PubMed does not use this as an indexing term, but instead uses Stress Disorders, Post-Traumatic
- Scroll down the MeSH page to look at the Entry Terms.
Entry Terms again provide you with synonyms or alternative terms that might be used in the abstracts and titles of articles that don't have Stress disorders, Post-Traumatic as a Medical Subject Heading.
If you scroll further down the page you'll see that MeSH has another option - Stress Disorders, Traumatic. Clicking on this will display the following
You may decide that all of these categories would be of interest to you. If you search Stress Disorders, Traumatic[mh] in PubMed it will automatically search the more specific categories listed beneath it. This is called "exploding" a term, and PubMed is the only database which will do this automatically with all of its indexing terms.
- Now update your logic grid
Cognitive Therapy
|
PTSD
|
| cognitive therapy[mh] |
stress disorders, post-traumatic[mh] |
- Although lists of Entry Terms give you ideas for words to search in titles or abstracts, you will probably think of additional possibilities. Add terms to the logic grid to allow for synonyms and other alternative terms - the list below is not intended to be comprehensive, but will give you an idea of how to build a search. If phrases are to be searched in titles and abstracts, most databases use inverted commas to enclose the phrase, and ensure that words are not searched independently. PubMed does not require this.
Cognitive Therapy
|
PTSD
|
Cognitive therapy[mh]
Cognitive therap*[tiab]
Cognition therap*[tiab]
Cognitive psychotherap*[tiab]
Cognitive behavior therap*[tiab]
Cognitive behaviour therap*[tiab]
Cognitive behavioural therap*[tiab]
Cognitive behavioral therap*[tiab]
CBT[tiab] |
Stress disorders, post-traumatic[mh]
Ptsd[tiab]
Post traumatic stress[tiab]
Posttraumatic stress[tiab]
Post-traumatic stress[tiab]
War neuros*[tiab]
Combat stress[tiab]
Combat neuros*[tiab]
Traumatic stress[tiab]
Shell shock[tiab] |
Here is what your record of your PubMed strategy should look like.
Logic
When you have finished collecting terms you are ready to search. PubMed requires that Boolean operators are in upper case, so it's important when searching PubMed to use AND, OR, NOT to connect your search terms. PubMed's tutorial gives a clear explanation of how Boolean logic works.
You will need to OR the individual words in each column, and then AND the groups of words together.
This is how the search will appear :-
Stress disorders, post-traumatic[mh] OR Ptsd[tiab] OR Post traumatic stress[tiab] OR Posttraumatic stress[tiab] OR Post-traumatic stress[tiab] OR War neuros*[tiab] OR Combat stress[tiab] OR Combat neuros*[tiab] OR Traumatic stress[tiab] OR Shell shock[tiab]
AND
Cognitive therapy[mh] OR Cognitive therap*[tiab] OR Cognition therap*[tiab] OR Cognitive psychotherap*[tiab] OR Cognitive behavior therap*[tiab] OR Cognitive behaviour therap*[tiab] OR Cognitive behavioural therap*[tiab] OR Cognitive behavioral therap*[tiab] OR CBT[tiab]
When you have long lists of terms it's much easier to search each column separately, then combine them. When searching each column separately you don't need to use parentheses around the groups of terms.
- Copy and paste the first set of terms into PubMed, and search
- Now copy and paste the second set of terms into PubMed, and search
- Once you have performed the two searches click on the Advanced search option - top right of the PubMed search screen. This will display your search history, and allow you to combine the results - using AND.
Useful Tips
- Open two tabs or browser windows when searching PubMed - this will allow you to have MeSH open in one, and PubMed open in the other. That way it's easy to move between looking up terms and testing searches.
- Look in the Details box (right hand side of the search screen) to see how PubMed has interpreted your search
- Click on the Title of an article to see MeSH terms used to index it
- Use the Entry Terms lists in MeSH to find words to search in titles and abstracts - remember MeSH alone will not produce a comprehensive search
- Expert Searching in PubMed
This is a single page guide produced by the Countway Library at Harvard University. Don't be put off by the "expert" - it's a very useful and easy to follow guide with lots of examples to help you to take advantage of PubMed's incredible search power.
PsycINFO
Unfortunately the same search cannot be simply copied and pasted into another database. Although there may be many similarities, field names and abbreviations will be different, and the user interface will sometimes require a slightly different method.
PsycINFO also has a Thesaurus of indexing terms but they may be rather different from PubMed's MeSH terms. Unlike PubMed it does not automatically explode terms from its thesaurus - you have to instruct it to do so.
The method you use to search will be similar
First look up your terms in its Thesaurus. As you can see from the image below the PsycINFO terminology for PTSD is quite different from PubMed's.
and the PsycINFO Thesaurus allows searching not just of cognitive therapy, but specifically of cognitive behavior therapy
Allow for additional words in titles and abstracts, as you did in PubMed, to extend the range of your search. PsycINFO does not allow you to search titles and abstracts together so you need to do separate searches for terms in each field.
NOTE:-
- In PsycINFO, when searching for phrases in titles or abstracts you must use inverted commas to make sure the words are searched together as a phrase, not separately.
- Type your search directly into the search boxes - don't attempt to copy and paste from a Word document. PsycINFO doesn't like Word inverted commas around phrases, but recognises only its own style!
Cognitive Therapy
|
PTSD
|
DE cognitive behavior therapy
DE cognitive therapy
TI “cognitive therapy”
AB “cognitive therapy”
TI “cognitive behavior therapy”
AB “cognitive behavior therapy”
TI “cognitive behaviour therapy”
AB “cognitive behaviour therapy”
TI “cognitive behavioural therapy”
AB “cognitive behavioural therapy”
TI “cognitive behavioral therapy”
AB “cognitive behavioral therapy”
TI CBT
AB CBT |
DE posttraumatic stress disorder
DE traumatic neurosis
DE stress reactions
TI Ptsd
AB Ptsd
TI “post traumatic stress”
AB “post traumatic stress”
TI “posttraumatic stress”
AB “posttraumatic stress”
TI “post-traumatic stress”
AB “post-traumatic stress”
TI “war neuros*”
AB “war neuros*”
TI “combat stress”
AB “combat stress”
TI “combat neuros*”
AB “combat neuros*”
TI “traumatic stress”
AB “traumatic stress”
TI”shell shock”
AB “shell shock” |
Here is what your record of your PsycINFO strategy should look like
Logic
You will need to OR the individual words in each column, and then AND the groups of words together. In PsycINFO, as in PubMed, when searching each column in a separate box, you don't need to use parentheses around the groups of terms.
This is how the search will appear :-
DE posttraumatic stress disorder OR DE traumatic neurosis OR DE stress reactions OR TI Ptsd OR AB Ptsd OR TI “post traumatic stress” OR AB “post traumatic stress” OR TI “posttraumatic stress” OR AB “posttraumatic stress” OR TI “post-traumatic stress” OR AB “post-traumatic stress” OR TI “war neuros*” OR AB “war neuros*” OR TI “combat stress” OR AB “combat stress” OR TI “combat neuros*” OR AB “combat neuros*” OR TI “traumatic stress” OR AB “traumatic stress” OR TI”shell shock” OR AB “shell shock”
AND
DE cognitive behavior therapy OR DE cognitive therapy OR TI “cognitive therapy” OR AB “cognitive therapy” OR TI “cognitive behavior therapy” OR AB “cognitive behavior therapy” OR TI “cognitive behaviour therapy” OR AB “cognitive behaviour therapy” OR TI “cognitive behavioural therapy” OR AB “cognitive behavioural therapy” OR TI “cognitive behavioral therapy” OR AB “cognitive behavioral therapy” OR TI CBT OR AB CBT
Using PsycINFO's Advanced search
- Type the first set of terms into the first search box
- Now type the second set of terms into the second search box
Alternatively you could perform each search separately, and combine them from the search history page.
Other databases
There may well be databases, apart from PubMed and PsycINFO, that are useful for your topic, and I've included a list of additional databases I think may be relevant for psychology.
The biggest of these is Scopus, and although it doesn't have the sophisticated subject search capability of PubMed or PsycINFO it has some extremely useful features which will allow you to extend your search with very little effort. Its greatest strength is its citation searching capacity. You can easily "translate" a PubMed search for Scopus, and while it may produce many of the same articles, there will be lots of additional material, and you will have some extra options available.
To see these additional features:-
- Try copying the title of a really good article from PubMed, and pasting it (enclosed in inverted commas) into the Scopus Search box.
"A systematic review on the effectiveness of cognitive behavioral therapy for posttraumatic stress disorder"
- Set the in box to Article Title, and search
- Once the result is displayed click on the title of the article
This will allow you to see
- the abstract for the article
- articles which have cited this article
- the list of references from the bibliography at the end of the article, along with a link to other articles which have cited each reference
Each reference in the list also has links to full text, as well as its own abstract and references.
Systematic Reviews
What is a systematic review?
By Pippa Hemingway and Nic Brereton. 2nd. ed. Hayward Medical Communications, 2009.
Systematic Reviews: CRD's guidance for undertaking reviews in healthcare
Guidelines developed and published by the NHS Centre for Reviews and Dissemination, which can be used as a framework for carrying out systematic reviews or used for information by organisations commissioning reviews.
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