Psychology: Advanced Literature Searching

Click on the links above for charts for field names wildcards and proximity operators.

Last updated Jan 30, 2018

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. These notes are to help you with both.

It is particularly important that all search terms, and the structure of your search are recorded accurately so that your search can be replicated.
You will find that if you intend to publish you will often be asked to provide details of your search strategy, and these will be evaluated by the reviewers prior to acceptance of your manuscript.

Creating a table, or logic grid, of your search terms in a Word document makes both the terminology and structure transparent, and allows easy replication of your search by anyone with access to the database in question. The article below elaborates on the importance of this.

Hale K., Koenka A. C., Sanchez C., Moshontz H., and Cooper H. (2014)
Reporting standards for literature searches and report inclusion criteria: making research syntheses more transparent and easy to replicate.
Research Synthesis Methods, doi: 10.1002/jrsm.1127.
(Article first published online: 24 SEP 2014)

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 mental disorders, and you talk about mental 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 synonymous alternatives as you can. Some of them  even have their own indexing language, or thesaurus, which needs to be considered as well.

We’ll begin with PubMed, followed by PsycINFO, and Embase, using the following topic as an example

cognitive therapy of PTSD

Many postgraduate topics will be more complex, but this is a simple example to demonstrate general principles. As long as you understand these principles you will be able to construct even highly complex searches.

The first step in any search, and the most time consuming, is the construction of an appropriate list of terms for each database you intend to search. PubMed, Embase, and PsycINFO all have different indexing languages, so you will need to create a separate search strategy for each one.

Click on the links below for notes (with some short videos) on how to perform this search on each database.

Systematic reviews (in the strictest sense) require extremely rigorous searching, and include grey literature, but in practice the term "systematic review" is used to refer to a range of approaches, from exhaustive searching of the literature, involving many databases, and including searching grey literature, to searches involving a predetermined set of databases, with no consideration of grey literature.

Before embarking on a systematic review, always check with your supervisor to clarify what is expected in terms of the range of databases, and other sources to be searched.

Below are some links which should help to clarify what is involved.

Systematic reviews and meta-analyses: a step-by-step guide
From the Centre for Cognitive Ageing and Cognitive Epidemiology at the University of Edinburgh.

What is a systematic review?
By Pippa Hemingway and Nic Brereton. 2nd. ed. Hayward Medical Communications, 2009. 

Finding studies for systematic reviews: a resource list for researchers
Provides a list of databases recommended by the Centre for Reviews and Dissemination at the University of York. However not all of these databases may be relevant for a particular topic.

The Joanna Briggs Institute  Systematic Reviews
General information on systematic reviews as well as useful information on levels of evidence.

PRISMA
PRISMA is an evidence-based minimum set of items for reporting in systematic reviews and meta-analyses. While its focus is on the reporting of reviews evaluating randomized trials, it can also be used as a basis for reporting systematic reviews of other types of research.  Since its release in 2009 the PRISMA statement has been endorsed by the Cochrane Collaboration.

The PRISMA Checklist provides a series of points to consider when conducting a systematic review. Of particular relevance is item 8 (in the Methods section).
Present full electronic search strategy for at least one database, including any limits used, such that it could be repeated.
It is essential that literature searches can be readily replicated, and providing a logic grid makes this a simple procedure.

PROSPERO
PROSPERO is the first open access online facility to prospectively register systematic reviews.

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.