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Research Tips: Finding the Evidence

Research tips, support, strategies and FAQs

Focus the Question

The first step in finding the evidence is to ask the right question!

There is an art to constructing a clinical question in such a way that you maximise your chances of finding meaningful information in an efficient manner.

For example, imagine the following scenario:

Your patient is a thirty year old woman, 14 weeks pregnant with her first child.  On an initial antenatal visit she is found to have a BMI of 32, putting her in the obese range.  You are concerned about the risk of adverse outcomes for the woman and her baby, especially if she gains a lot of weight during her pregnancy.  You wonder whether dietary or lifestyle interventions could help your patient limit her weight gain during the remainder of her pregnancy.


One approach to turn our scenario into a clinical question is to use the PICOT formula.  This helps us to pick out the key point from our scenario.

P = Patient or Population or Problem

"thirty year old woman, 14 weeks pregnant with her first child.....BMI of 32"

I = Intervention

"dietary or lifestyle interventions"

C = Comparison

usual care

O = Outcome

"limit her weight gain during pregnancy"

T = Type of study

Question = therapy; study type = RCT or systematic review


The next step is to translate the key points we have identified into keywords. 

When considering keywords, it is important to choose terms which will help us find the information we need, without narrowing down our search too much.  For example "BMI of 32" is too specific; "obese" would be a better term. 

We also need to consider synonyms, or alternative terms, for our keywords, in order to capture as many relevant articles as possible.  For example, alternative terms for "lifestyle intervention" could include "exercise" or "diet".

Next we need to consider dropping some terms which may be redundant.  For example, if we include the term "pregnant" or "antenatal" we don't need the term "woman".  If the comparison is "usual care", we don't need to specify this in our keywords.

Finally, we need to think how to form our terms into an effective search strategy.  We combine alternative terms with OR and terms for different concepts with AND.

We could end up with something like this:

obese OR overweight


pregnant OR pregnancy OR antenatal OR prenatal


lifestyle OR diet OR exercise


weight gain OR excessive weight

limit to Systematic Reviews or RCTs.


The table below explains how Boolean Operators (AND, OR, NOT) work

Tutorials on formulating a clinical question

Formulate a Clinical Question UWA Faculty of Medicine, Dentistry & Health Science

Find the best evidence UWA Faculty of Medicine, Dentistry & Health Science

The well-built clinical question: a key to evidence-based decisions. Richardson, WS. et al. ACP Journal Club, v123:A12, Nov-Dec, 1995.

Find the Evidence

Where do I find the evidence?

There are a host of medical databases, and it can be difficult to know where to begin.  The most efficient method is to start at the top of the '6S Hierarchy of Evidence' (see What is EBP?) and work down.  This way you start by searching the most highly filtered resources, which may be able to give you a quick answer to your query.  Only after checking these do you work your way down to the unfiltered resources containing single studies which will take you time to appraise.  


Clinical decision-making tools, such as JBIBest Practice and Dynamed Plus, have already synthesised and summarised the evidence on many topics for you.  You may also find it useful to look at local and international guidelines, including the WNHS Guidelines and RANZCOG Guidelines as well as those from the Australian Clinical Guidelines Portal , the NICE Guidance and NICE Pathways (UK). Also see the Guidelines & EBP Resources tab.


If you do not find the answer to your query in the guidelines or clinical decision-making tools, you may be able to find a relevant systematic review.  The Cochrane Library provides access to systematic reviews, as does TRIP and the PubMed clinical queries search.


If your query relates to a less common topic, the evidence may not yet have been synthesised.  In this case you will need to use unfiltered resources to look for original studies, and then appraise them yourself.  You will also need to find original studies if you are involved in research, or in producing or updating guidelines, since filtered resources will often not include the very latest, cutting-edge research.  Databases in which you can find quality single studies include: MedlinePubMed; Emcare; PsycInfoEmbase.  For a complete list of relevant databases, consult the subject guide for your area of interest.


Alternatively, this table gives examples of clinical questions matched with selected databases.