COLUMNS

THE JOURNEY TO EVIDENCE-INFORMED NURSING PRACTICE

Tips for identifying the best available evidence

by Maureen Dobbins

Maureen Dobbins

First, I want to wish everyone a happy, healthy and safe 2008. A new year is a time to reflect on where we’ve been and where we are going, or would like to go. However, to be honest, as I look out my window on a blustery January morning, I would really like to be heading to a hot, sunny beach, but I digress. It has been an absolute pleasure writing these columns this past year and, as a result of your positive feedback, I am happy to continue writing about evidence-informed nursing practice.
 
To recap 2007, I started the series with a historical look at the evidence-informed practice movement in nursing and, more generally, in health care, that has led us to the current state of knowledge and activity. This was followed by a broad overview of the process of evidence-informed nursing practice, with suggestions on how to articulate a clear and concise practice- or policy-based question. My last column explored pairing research questions with optimal research designs.

In 2008, I plan to address the following: 1) tips for identifying the best available evidence; 2) criteria to assess the methodological quality of single studies that evaluate the effectiveness of an intervention; 3) criteria to assess the methodological quality of reviews that evaluate the effectiveness of an intervention; and 4) criteria to assess the methodological quality of single qualitative studies, using a phenomenological design.

For those wanting to become more knowledgeable about the criteria used to assess methodological quality for other research designs, there are a number of good evidence-based nursing textbooks to refer to. For those who prefer face-to-face interaction, several multiday workshops are offered in North America and worldwide, usually during the summer months.

We resume our journey toward evidence-informed practice by exploring tips for identifying the best available evidence. For those of you who spend countless hours searching databases such as MEDLINE and CINAHL, only to come up empty-handed or unsure if you found all of the important evidence, I hope these tips will provide new insights that, while not making the task of searching enjoyable, will at least make it more successful. (If you haven’t guessed already, I am not a librarian. For me, searching is more akin to a chore than a coveted extracurricular activity.)

First and foremost, evidence-informed practice is based on the premise that, during the decision-making process, one should use the best available evidence from a synthesized body of knowledge rather than single studies. This implies there is a hierarchy of evidence quality, determined by the extent to which evidence has been synthesized. One of the most useful models for depicting this hierarchy was developed by Haynes (2007). As illustrated in the pyramid below, the search for evidence begins at the systems level and only proceeds downward in the hierarchy when no evidence exists at a higher level, or if available evidence is not of the highest methodological quality.

Again, start searching for systems level evidence, i.e., electronic medical records. If nothing exists at this level, move down to summaries, i.e., clinical practice guidelines, then to synopses of syntheses (systematic reviews), then syntheses and so on. Only when you are confident that no evidence exists higher up in the hierarchy should a search for single studies be conducted. Using a framework such as this will help you focus your search and, in many cases, particularly at the higher levels, lead you to good-quality evidence.

If you do find yourself searching for evidence in PubMed or CINAHL—whether single studies or systematic reviews—a powerful tool is “clinical queries.” In essence, clinical queries are predetermined sets of search terms proven to identify specific research designs and/or research questions. For example, if you want to know how effective an intervention is for achieving a specific outcome, conduct a search using keywords related to that intervention and outcome. Then use clinical queries to limit your search to randomized controlled trials or systematic reviews. Now, when you run your search, clinical queries will add all the keywords necessary to find randomized controlled trials or systematic reviews. The result is a more focused and specific search.

Searching is definitely an acquired skill that takes time and practice. I encourage you to practice searching using the hierarchy presented above. It will lead to greater success in finding the evidence you need in a shorter period of time.

In my next column, I will discuss essential criteria needed to assess the methodological quality of single studies that evaluate effectiveness of interventions. I start with single studies because the skills needed to assess the quality of intervention studies establish the foundation for assessing synthesized evidence higher up on the pyramid of evidence. RNL

Maureen Dobbins, RN, PhD, associate professor at McMaster University School of Nursing in Hamilton, Ontario, Canada, is a founder and primary investigator for www.health-evidence.ca, a free, searchable online registry of public health review evidence that saves researchers time and effort in locating, screening and assessing the quality of evidence for improved decision making. Dobbins holds cross appointments with the School of Rehabilitation Sciences and the City of Hamilton Public Health Services.

Reference:
Haynes, B. (2007). Of studies, syntheses, synopses, summaries, and systems: The "5S" evolution of information services for evidence-based healthcare decisions. Evidence-Based Nursing, 10(1), 6-7.