Q&A About Evidence

Q. What is evidence, and evidence-based practice?

Dictionaries generally define evidence as anything that establishes a fact or gives reason to believe something. Evidence-based practice has a range of meanings. There are many definitions of evidence-based care, the first of which is the widely accepted definition by Sackett et al., (1996): "the conscientious, explicit and judicious use of current best practice in making decisions about the care of individual patients". EBP can also be defined as an approach to clinical decision making in which the clinician uses the best research-based evidence available, in line with his/her clinical experience and in consultation with the patients. In short, EBP is nothing else that questioning the practice we do!

Q. What is the purpose of evidence-based practice?

Its purpose is to deliver best practice, i.e., the highest quality care to individual patient. To achieve this, practitioners need to be able to critically evaluate their current practice and apply what they have learnt from evidence-based practice. They must also learn to adopt a process of evidence-based practice that is open to scrutiny by their peers and the public. By being open and transparent, clinical decisions can be justified and accountability demonstrated.

Q. Is there such a thing as a hierarchy of evidence?

Yes. Some types of evidence are better or more credible than others. Hierarchies of evidence refers to ranking systems developed by researchers and practitioners to identify the ‘best’ evidence they can apply to practice. The body of evidence is often ranked, from top to bottom, as primary, secondary and tertiary sources. Primary sources of evidence, drawn on original research findings, include randomized controlled scientific research articles (RTCs) gathered from human and animal populations. RCTs have a clear methodology using randomisation of study participants and interventions and control groups. They are published in peer-reviewed journals. Secondary sources of evidence include systematic reviews, meta-analyses, clinical guidelines and case studies. Tertiary sources of evidence include expert opinions and views of colleagues and peers.

Q. How can I become a better evidence-based practitioner?

To practice evidence-based care you need to be critical and ask questions about the care you are providing and not just take for granted that it is the best way of doing it. To do so you need to gather, appraise, and act on the evidence. Here are some key questions to ask about the evidence. Does it come from a primary, secondary or tertiary source? What is the evidence telling you and what does it mean? Does the evidence answer your question? Acting on evidence is where you have decided, following your critical appraisal, that the evidence is credible enough, and that it should be incorporated into your clinical practice. To help to incorporate this evidence into your practice, you will need to draw upon your own expertise, experience and knowledge of your patient population and clinical area. You will need to consider both the benefits and risks of implementing any changes, as well as the benefits and risks of excluding any alternatives. Change can be difficult to achieve if not approached in an appropriate way, and resistance to change can be a big problem. Always remember that evidence-based practice (EBP) is all about questioning what you are doing!

Q. What's the bottom line on evidence-based practice?

  • Evidence-based practice (EBP) is a process, rooted in science, which comes only to full maturity through the art of clinical expertise and judgment, and patient participation.
  • EBP is not is a cookbook where recipes (research protocols and findings) are applied to patients.
  • EBP is a highly complex and easily misunderstood term. Arguably, the most common misconception is that evidence “rules”, and that clinical  judgment and patient preferences and values have no place in an EBP approach to decision-making. Another related misconception is that EBP is all about research designs, numbers and statistics. As it turns out, none of the above is true. To entertain these misconceptions only sells the concept of evidence-based practice short.
  • Clinical judgment is needed put EBP into proper perspective.
  • EBP informs but never replaces the clinician’s judgment.
  • Both clinical expertise and judgment are required to determine if the evidence is suitable and if so, how it should be applied.
  • EBP is nothing else that questioning the credibility level of our practice.