What Is Evidence-Based Practice?

What Is Evidence-Based Practice?

Evidence-based practice: What it is and how it can be properly utilized?

Evidence-based medicine, whose philosophical origins extend back to mid-19th century Paris and earlier, remains a hot topic for clinicians, public health practitioners, purchasers, planners, and the public.

What is evidence-based practice?

Sackett et al. defines evidence-based practice as the integration of the current best research evidence with clinical expertise and patient values. The practice of evidence-based medicine integrates individual clinical expertise with the best available external clinical evidence from systematic research.

Individual clinical expertise includes skills, proficiencies, and judgments that clinicians acquire through clinical experience and clinical practice. This heightened expertise is reflected in many ways, including more effective and efficient diagnosis, more thoughtful identification, and compassionate use of individual patients’ predicaments, rights, and preferences in making clinical decisions about their care.

Related: Foundations of Evidence-Based Practice

Elements of evidence-based practice

The three components to evidence-based practice are:

  1. Best available evidence
  2. Clinicians' experience, knowledge, and skills
  3. The patient’s needs wants, and beliefs

The American Physical Therapy Association breaks down these components, giving equal value to each. From their website: “APTA supports the development and use of evidence‐based practice that integrates best available research, clinical expertise, and patient values and circumstances.”

To determine the best available evidence, physical therapists must incorporate the best evidence from well-designed studies. A variety of rating systems and hierarchies of evidence grade the strength or quality of evidence generated from a research study or report.

Understanding the strength of these systems is vital for every clinician. Clinicians need to be confident on how much emphasis they should place on a study, report, practice alert or clinical practice guideline when making decisions about a patient’s care.

Levels of research

Evidence-based information ranges from Level A (the strongest) to Level C (the weakest). In 2013, Level ML, multilevel, was added to identify clinical practice guidelines that contain recommendations based on more than one level of evidence.


Evidence obtained from:

  • Randomized control trials. The classic “gold standard” study design. In RCTs, subjects are randomly selected and randomly assigned to groups to undergo rigorously controlled experimental conditions or interventions.
  • Systematic review or meta-analysis of all relevant RCTs. A systematic review is a critical assessment of existing evidence that addresses a focused clinical question. It includes a comprehensive literature search and appraises the quality of studies and reports results in a systematic manner. Meta-analysis is a study design that uses statistical techniques to combine and analyze data from many RCTs.
  • Clinical practice guidelines are based on systematic reviews of RCTs. Evidence-based clinical practice guidelines provide the strongest level of evidence to guide clinical practice because they are based on rigorous reviews of the best evidence on specific topics.


Evidence obtained from:

  • Well-designed control trials without randomization. In this type of study, researchers do not use random assignment to assign subjects to experimental and control groups. Therefore, this type of research is less strong in internal validity. It cannot assume the subjects in the study are equal on major demographic and clinical variables at the beginning of the trial. Frequent problems with this type of study include intentional or unintentional bias in sample enrollment; nonblinding, unclear criteria for participant selection; or unreliable or invalid tools.
  • Clinical cohort study. An examination of groups of people who have common characteristics or exposure experiences to compare outcomes in those exposed vs. outcomes in those not exposed (e.g., development of heart disease after exposure or non-exposure to 10 years of secondhand smoke).
  • Case-controlled study. Use of an observational approach in which subjects known to have a disease or outcome are compared with subjects known not to have that disease or outcome. Subjects are matched on characteristics so that they are as similar as possible except for the disease or outcome. Case-control studies are generally designed to estimate the odds (using an odds ratio) of developing the studied condition or disease and can determine if an associated relationship exists between the condition/disease and risk factors.
  • Uncontrolled study. Studies that do not control participant selection or interventions (e.g., a convenience sample, such as patients on a given unit, may be studied because it is the only group reasonably available).
  • Epidemiological study. Studies that observe people over a long time to determine risk or likelihood of developing diseases. These studies include retrospective database searches or prospective studies that follow a population over time.
  • Qualitative study/quantitative study. Descriptive, word-based phenomena, such as symptoms, behaviors, culture, and group dynamics. Quantitative studies use statistical methods to establish numerical relationships that are correlational or cause and effect.


Evidence obtained from:

  • Consensus viewpoint and expert opinion. A study that obtains agreement about specific practices from all clinical experts on a review panel. Expert opinion involves obtaining agreement from a majority of clinical experts on a review panel. Note: Use this level of evidence when there are no quantitative or qualitative studies in a particular area.
  • Meta-synthesis. A systematic review that synthesizes findings from qualitative studies using an interpretive technique to bring small study findings, such as case studies, to clinical application.

LEVEL ML (multilevel)

Clinical practice guidelines, and recommendations based on evidence obtained from:

  • More than one level of evidence as defined in the rating system.

The clinician angle

After taking into evaluating research studies, consider the clinician’s knowledge and skills. This accumulation of knowledge, patient care experience, treatment decisions and outcomes make up a critical part of evidence-based practice.

According to Sackett, “clinical expertise is not just an afterthought. If it is not, integrated practice risks becoming tyrannized by evidence. Even excellent external evidence may be inapplicable to or inappropriate for an individual patient.”

The patient’s needs

Finally, consider the patient’s needs, wants, and beliefs. Patient preferences can include religious or spiritual values, social and cultural values, thoughts about what constitutes quality of life, personal priorities, and beliefs about health.

The ASK (AskShareKnow) is a valuable Patient–Clinician Communication Model. This tool to teaches patients and families three questions to ask their healthcare providers to get information they need to make healthcare decisions:

  1. What are my options?
  2. What are the possible benefits and harms of those options?
  3. How likely are each of those benefits and harms to happen to me, and what will happen if I do nothing?

Related: Evidence Based Approach to Rehabilitation of Achilles Tendon Injuries

A guide, not a cookbook

Sackett et al. summed it up well by saying “Evidence-based medicine is not ‘cookbook’ medicine. Because it requires a bottom up approach that integrates the best external evidence with individual clinical expertise and patients’ choice, it cannot result in slavish, cookbook approaches to individual patient care.

“External clinical evidence can inform, but can never replace, individual clinical expertise. It is this expertise that decides whether the external evidence applies to the individual patient at all and, if so, how clinicians should integrate it into a clinical decision.

“Similarly, clinicians must integrate any external guideline with individual expertise when deciding whether and how it matches the patient’s clinical state, predicament, and preferences, and thus whether they should apply it. Clinicians who fear top-down cookbooks will find the advocates of evidence-based medicine joining them at the barricades.”

This article was adapted from our sister site, Elite Learning, written by Kristen Digwood, MSPT, DPT, CLT.

This article was written by Mehreen Rizvi

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