Health Informatics in Clinical Practice

Information Hierarchy


It has been estimated that there are about 5,000 articles published every month in the biomedical journals. Out of this, only about 5% represents high quality research.

Therefore, it is important to be able to establish a clear hierarchy for all the information that is available.

Furthermore, a distinction needs to be made between "data" and "information".

The former can be defined as a set of discrete objective facts or values that does not have any attached meaning or context, whereas the later can be defined as "Data" that has been organised and processed, and is able to instruct or inform the user.

"Knowledge" may then follow when the sum of what is known is integrated and applied using skills gained through further education, practical experience and training.

The Pyramid Hierarchy of Information


This hierarchy can be represented in the shape of a pyramid. The base of this pyramid would represent all the articles in all the biomedical databases (note that Medline is a subset of the Pubmed database).

The Medline database contains over 12 million records of these types of clinical information. They can be considered as the "primary source" of clinical information. Although massive in volume, they are virtually inaccessible in the real world clinical setting due to the sheer amount of work required to separate the wheat from the chaff.

One study have shown that it takes an experienced librarian trained in search strategies up to 43 minutes just to find the evidence required to answer one clinical question. After that much more time and effort would still be required to assess the validity and relevance of the collected information.

More useful are the "secondary sources" of information.

These consist of the peer-reviewed medical journals and databases such as the Evidence-based Medicine journal, the American College of Physician Journal Club journal and the Cochrane Database of systematic reviews.

The papers in these journals have been selected for their scientific rigor and validity.

Validity means that the researchers have taken steps to address bias, confounding factors and have answered the question that the researchers had originally set out to answer.

They represent only about 5% of the total biomedical research pool.

In recent years, a substantial body of "tertiary source" of information have also been developed. In addition to having rigorous scientific research methods, the information produced is also examined for their clinical relevance by practising experts in each particular field.

It is only at this level that clinical research become "useful" in the clinical setting. Not only must the information be valid, it must also be relevant to the patient.

Relevance means that the application of the information must influence the outcomes most important to the patient. This usually means a symptom free and functional life, and not just a prolongation of life.

The two main sources of tertiary clinical information at present are the UpToDate and Essential Evidence Plus (previously known as "InfoRetriever") services.

The Map of Medicine service is a recent addition in this group, focusing on Evidence-based care pathways and referral processes in the NHS system. Clinical guidelines developed by the Scottish Intercollegiate Guidelines Network (SIGN) and the technology appraisals by the National Institute for Health and Clinical Excellence (NICE) can also be considered as belonging to this group. The Cochrane Reviews are generally recognised as the highest standards in evidence-based health care, adressing clearly formulated questions via systematic reviews.

The main drawbacks to the last group is that they are labour and time intensive, hence are only available to cover a limited number of clinical conditions.

The Equation Defining "Useful"

Slawson and Shaughnessy have proposed the following equation to define "useful" information.

U = V x R / W


U = Usefulness of the information,

V = Validity of the information,

R = Relevance of the information and

W = Work required to find the information.

The Ideal Source of Information

Therefore, one can propose a "fourth level" of clinical information where tertiary sources of information can be accessed seamlessly in the clinical workflow via an integrated electronic health care record service at the point of care.

This would ensure that more clinical questions are asked and answered at each and every clinical encounter.

With the current technological advancement in

it is conceivable that in the near future, clinicians will automatically be offered a selection of individualised high quality, relevant and up-to-date data for each patient. A "multi-modal" intelligent user interface will complement this system and allow the clinician to focus on the doctor-patient interaction and minimise the need for manual log-ins, data entry and identification of useful clinical information.

To quote Doughlas Carnall, "Good software forms seamless connections; as George Orwell said of prose" (pdf)


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Page Updated: 17 May, 2017

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