The increasing need to incorporate patient preferences and value in clinical decisions has necessitated the need for evidence-based practice (Buie, 2010). Evidence-based practice is a conscious approach that incorporates patient values and preferences, while integrating latest solid clinical evidence and nurse expertise in clinical decision-making in the delivery of health care. Unfortunately, there are thousands of nursing journals being published in the US every year and the lack of a standard formula for weighing the factors. However, a number of levels for rating the clinical research have been developed.
The Levels of Evidence
Generally, the clinical research levels of evidences have a range from the strongest (Level A) to the weakest (Level C). However, some experts have included an extra level (ML), the multilevel, which is used in the identification of the clinical guidelines containing recommendations that is based on one or more of the clinical levels of evidence (Nurse.com, 2015).
The evidence obtained from level A includes the randomized control trials, systematic reviews and clinical practice guidelines (Nurse.com, 2015). In randomized control trials, the evidence involves a clinical study that uses randomly selected subjects that undergo a rigorously controlled intervention or condition. Systematic reviews involve a study done on a critical assessment and appraisal of current clinical studies, with focused research questions. The study further does a comprehensive literature reviews in order to systematically appraise its quality, and the quality of the sources used in its reports and analysis.
The evidence obtained from level B includes cohort studies, well-designed non-randomized controlled clinical trials, quantitative/qualitative studies, and epidemiological studies, uncontrolled and controlled-case studies (Burns, Rohrich, & Chung, 2011). In the uncontrolled studies, the evidence is obtained from specific subjects who might be available at that time, for example patients in a hospital unit. The epidemiological studies involve a study that runs over time in order to observe the risks or likelihoods of the development of a particular disease. In cohort studies, a group of subjects with similar exposure experiences or characteristics is examined and the results compared amongst the exposed vs. the non-exposed subjects.
A case-controlled study involves an observational comparison of subjects who have and those who have not developed a condition or disease. The subjects are grouped based on similarity of characteristics except the similarity in the condition. Finally, the qualitative/quantitative studies involve descriptive and statistical analysis of cause and effect.
The evidence under this level is obtained from an agreement between the experts views regarding the best clinical practice for a specific clinical condition and meta-synthesis, where a systematic review of qualitative studies is done in order to bring the findings of such a study into clinical application.
Why the Levels of Evidence Are Important Regardless Of the Method One Uses
When clinical research studies are published, the authors assign them the levels to which the journals can be categorized (Burns, Rohrich, & Chung, 2011). Although having knowledge of the level of the evidence to which the research studies are categorized, it may not guarantee the quality of the research article. Therefore, regardless of the level or method one uses to categorize levels of clinical evidence, it is important that the evidence is appraised to ascertain its solidity.