The TRIP Process

The TRIP process consists of the following elements:

Introduction to the TRIP Process

The TRIP Database has evolved into a sophisticated tool for locating the highest possible evidence with which to inform clinical decisions, using the principles of evidence based medicine. This section will highlight the methods used in the TRIP Database from 'Content Identification' through to 'Results Display'. In addition we will briefly discuss the other main clinical content on the site.

Content identification

The content of the TRIP Database is identified using a variety of methods. Initially, all records were identified using Netting the Evidence website (a site dedicated to recording sites of interest to practitioners of evidence based medicine). However, as the site grew additional methods were found to identify new sources. This includes systematic searches of the internet, reports in the literature, self-reporting by site owners and other recommendations. Another important method is to liaise with clinical question answering services such as the NLH Q&A Service and ATTRACT to see what quality resources they use to answer clinical questions. If they are finding a resource clinically useful we endeavour to incorporate the content into the TRIP Database.

We also work closely with Department of Family Medicine at Laval University, Quebec, Canada to help identify and appraise sites in a more systematic manner. The current tool for evaluating sites is being re-evaluated to include new resources and favour a more global audience. This Directory of Clinical Information Websites is a web-based tool created and maintained by the Department of Family Medicine at Laval University. The Directory, offered in English and French, features over 100 critically appraised websites that mainly offer critically appraised topics (CATs) or original articles, systematic reviews and clinical practice guidelines (CPGs). All sites listed in the Directory are assessed and described using a validated evaluation instrument, using the principles of evidence based medicine

Once a site has been identified as potentially useful it is then assessed by an in-house team of information experts and clinicians and external experts to assess quality and clinical usefulness. If the site passes this additional test we start the process of 'grabbing' content

Content grab

The first stage is to identify the clinically relevant material within the website. Once this has been identified certain core information (title, URL and date of publication) is obtained, either manually or via an automated system. The next stage is for our in-house spidering software to visit every URL and grab the content of that page. This is then processed by our systems to remove superfluous material such as HTML coding etc. The material is then ready for searching and made live.

Search process

An initial search is undertaken to see if the entered term(s) match any records within the site. If none are found the system assumes a mis-spelling has occurred and will cross-reference the entered phrase against our mis-spelling dictionary and any suitable matches are displayed for the user to use.

Once a valid search term is entered the system carries out a search for matching keywords and/or synonyms.

In addition to the core site content, TRIP Database automatically searches Medline via PubMed. This search is facilitated by the use of the clinical queries search filters (based on the work of Haynes RB). These search filters restrict the search results to a specific clinical study category (currently etiology, diagnosis, therapy and prognosis).

We have even created a speciality filter to further focus searches in Medline (principally due to its size). The specialisation feature allows users to restrict searches of PubMed to core journals in a clinical area. PubMed currently indexes over 4,000 journals so by restricting a search to up to 20 key journals in a clinical speciality the results better serve the user.

NOTE: The TRIP Database also links specifically to two main sets of articles contained in PubMed. These are spidered and searched as part of the main TRIP results, these are:

1) The ‘Big 5’ general internal medical journals (NEJM, JAMA, Lancet, BMJ, Annals of Internal Medicine) for the last 5 years.
2) BMJ Updates.

Accessing primary research evidence via PubMed, using either our special filters or via those results included in the main TRIP search, points only to the abstract of the document.

Results display

The search results are returned based on the score for each matching record. This score is based on three main variables:

- Year of publication. The newer the article the higher the score
- Term position/density. This is the most complicated and is based on two main factors. Firstly, the position of the search term; a search term in the title scores higher than one just appearing in the text. Secondly, term density; the greater the search term density (number of appearances of the term divided by the total number of terms) – so a search term appearing once in a document scores lower than another, similar sized, document where it appears many more times.
- Publication. Each publication is given a score based on methodological quality and clinical usefulness. So a publication such as Cochrane (seen as the pinnacle of evidence based medicine) will have a higher score than something like GP Notebook.

Categorisation method

The content of the TRIP Database is separated into a number of categories. This categorisation is based on Haynes’s work on the 4S approach to current best evidence.

Evidence-based synopses. These are synopses of individual studies that have been critically appraised. This category includes evidence-based journal reviews, CATs, Clinical Evidence etc.
Clinical answers. A number of services exist to answer clinical questions. These services aim to match the best available evidence to the question.
Systematic reviews. These are explicit, rigorous syntheses of primary research studies.
Guidelines. Clinical guidelines are central to modern healthcare and we have gathered collections from around the globe. Given guidelines geographic sensitivity these have been separated according to the country/area of origin.
eTextbooks. These online textbooks tend to be excellent sources of background material.
Clinical Calculators.
Medline. Using a special interface the TRIP Database automatically searches PubMed using validated search filters to return highly-focussed results.

The TRIP Database also has separate sections for medical images and patient information leaflets.

Search tips

Using only one term can bring back a large number of results, so think of additional terms to help qualify the search e.g. asthma and steroids.

Phrase searching is achieved by placing the phrase within quotation marks.

In addition to Boolean searching you can also use brackets to enhance the search e.g. ‘(measles OR mumps) and pregnancy’

A search term can be stemmed by using the ‘*’ e.g. ‘cancer*’ will find cancer, cancerous etc.

On the results page you can filter your results based on an evidence based medicine hierarchy e.g. clinical guidelines, systematic reviews. Use the ‘Filter by’ function on the right-hand side of the screen.

For our top ten search tips click here.

For more extensive search tips click here