Nia Roberts, an outreach librarian in the medical sciences division at Oxford University, passes on her tips on how you can optimise your searches on the internet

What happens when a patient asks you a question and you do not know the answer? Where do you go to find the information if there is no national guideline to hand?

Research among primary care practitioners suggests that time is an important factor when searching for answers, and that most of them will consult sources close at hand, such as asking colleagues or checking locally held paper resources, with use of electronic resources further down the list.1,2 The research also highlights that there are other obstacles to using electronic resources, including the difficulty in forming a search, not knowing where to start, and the difficulty in synthesising the findings.1

Aim of the article

In recent years there have been developments in the provision of electronic resources in terms of: improved accessibility, ease of searching, and the way information is packaged. This innovation has increased the availability of evidence-based information that can be found and read quickly. This article looks at how to make the best use of the available evidence-based resources.

The PICO formula

When trying to find information quickly, it is tempting to dive straight in and start searching, but a little time spent thinking about what you are hoping to find can make all the difference. Formulating an answerable question has long been the starting point for practitioners of evidence-based medicine3 and is often referred to as the PICO formula. This can be useful for focusing on the problem in hand. The formula comprises:

  • P—what is your Patient/population group?
  • I—are you looking at a particular Intervention/exposure?
  • C—do you have a Comparator?
  • O—are you interested in particular Outcomes?

The PICO formula allows the user to focus on the search, but also helps in pinpointing the terms and phrases that he or she is going to use.

Searching electronic resources

There are a few key points to remember when searching electronic resources, whether you are looking at a search engine, an evidence-based resource, or a healthcare database. These are:

  • think about synonyms and variant spellings—for example, chronic fatigue syndrome/myalgic encephalomyelitis are often used for the same condition
  • combine search terms using ‘and’/‘or’—‘and’ focuses the search and is used for terms that describe different concepts, ‘or’ broadens the search and is used to combine synonyms: for example, chronic fatigue syndrome and cognitive behaviour therapy; chronic fatigue syndrome or myalgic encephalomyelitis
  • use a truncation symbol to find words that have the same beginning but which might have different endings—for example, behavio* for behavior, behaviour, behavioural, etc
  • use parentheses to group terms—for example, (chronic fatigue syndrome or myalgic encephalomyelitis) and (CBT or cognitive behavio* therap*).


Once you have taken a few minutes to think about what you are looking for, you need to decide where to start searching. These are a few freely available websites that I often use when searching for information to address clinical questions sent to me by health practitioners and researchers.

The Trip database

The Trip database ( was set up to allow busy clinicians to find evidence-based information quickly. It has a single search box, plus an option for an advanced search, in which you can enter search terms. It searches a range of resources and returns a set of results broken down into categories; for example, typing in the following terms (chronic fatigue syndrome or myalgic encephalomyelitis) and (CBT or cognitive behavio* therap*) yields 74 results. However, the categories allow you to select the most appropriate information for your needs rather than having to trawl through all 74 records. If you know nothing about a condition, you might have a look at a few e-textbooks to obtain a basic introduction, but if you are more interested in making treatment decisions, go straight to the systematic reviews, evidence-based synopses or guidelines.

Another time-saving aspect of Trip is the blue information icon. Rather than having to read a long systematic review, you can go straight to the conclusions by clicking on the blue information icon.

The National Library for Health

The National Library for Health (NLH) ( is useful for both searching and browsing. Repeating the previous search (chronic fatigue syndrome or myalgic encephalomyelitis) and (CBT or cognitive behavio* therap*) returns multiple results and you can choose to browse through the contents of individual categories, evidence-based guidance, or specialist libraries. NHS staff can search a range of healthcare databases, electronic journals, and e-books on the NLH—all that is needed is an NHS Athens username and password, which is obtained by registering online at

In addition to using the search engine, you can browse individual sections of the website. The clinical knowledge summaries provide overviews of common medical conditions, while the clinical Q&A answer specific questions submitted to the site by practising clinicians.

The Cochrane Library

The Cochrane Library ( is freely available in the UK. It can be searched using the same principles as above, and looks for systematic reviews, trials, technology assessments, and economic evaluations that provide evidence on the clinical and cost-effectiveness of interventions. In addition, this website also enables access to the full text of Cochrane systematic reviews.


Pubmed ( is a well known resource allowing free access to the Medline database. It is searchable using the same methods as above, which allows you to identify a large range of articles on a subject. However, in order to focus the search you can use the clinical queries section of the database, which allows you to limit searches by clinical study type. It can be restricted to systematic reviews, diagnosis, aetiology, therapy, prognosis, or clinical prediction guides, thus reducing the number of results.


Google ( can also be searched using the same methods as discussed previously. Think about the question, identify the search terms, and combine the terms to focus your search. There are a few other things that are worth knowing about Google: it automatically puts ‘and’ between words, so you should use inverted commas to search for phrases; and the truncation symbol * is ineffective. To repeat the previous search on Google, you need to type it in like this ("chronic fatigue syndrome” or "myalgic encephalomyelitis”)(cbt or "cognitive behavior therapy” or "cognitive behaviour therapy”), but faced with a large number of hits, it might take some time to find an evidence-based answer.


There are a number of options for busy clinicians to find evidence-based information, and I have only identified a handful here that I use on a daily basis. It is worth giving them a try the next time you get a difficult question from a patient.

  1. Coumou H, Meijman F. How do primary care physicians seek answers to clinical questions? A literature review. J Med Libr Assoc 2006; 94 (1): 55–60.
  2. Bryant S. The information needs and information seeking behaviour of family doctors. Health Info Libr J 2004; 21 (2): 84–93.
  3. Richardson W, Wilson M, Nishikawa J, Hayward R. The well-built clinical question: a key to evidence-based decisions. ACP J Club 1995; 123 (3): A12–13.G