Evidence based practice is a way to help nurses make decisions in clinical care guided by the best possible evidence. There are five stages in evidence based practice:
Click through the tabs on the box below to find out more about each stage.
The first step of evidence based practice is to form a clear clinical question. This will help you find the information you need.
PICO is a framework that can help you turn your question into search terms that will give useful results.
Not all questions will use every element, but it helps to be as specific as possible to help evaluate which results are relevant.
There are variations on PICO which you may need to use, depending on your question.
PICOS: Study type
This stage is where you search for information to answer your question. You can use your PICO elements to plan how to search.
When answering clinical questions, you need to use the highest level of evidence possible. In the diagram below, the higher up the pyramid, the higher the level of evidence is. Secondary research appraises the quality of studies and often makes recommendations for practice. Evidence is not always available from secondary research, and searching primary research may be required.
|Secondary research||Primary research|
A systematic review is regarded an a high level of evidence, and is secondary research. It starts with a specific and answerable clinical question, identifies all the research available and eliminates flawed and low-quality studies, then uses the results of the remaining high-quality studies to answer the clinical question and thus make recommendations on best practice.
Randomised controlled trials are primary research. Researchers assign participants randomly into an intervention group or a control group, then results are compared to see if the intervention had an effect.
A cohort study is primary research. It looks at health outcomes of a specified group, comparing people in the group who have been exposed to a potential risk factor with those who have not been exposed, and looks for links and correlations.
Case control studies looks at existing data to compare people who have a specific health outcome or condition, compared with those who don't, to find what factors differ between the groups.
Case series and case reports look at one or more individual cases and outcomes or responses to interventions. Regarded as a low level of evidence, the information might not apply to a wider population.
Editorials and expert opinions can be based on a practitioner's individual experience. Generally regarded as one of the lowest levels of acceptable evidence, they do not necessarily account for uncontrolled external factors, differences between different groups, nor placebo effects.
Hover over each level of the evidence pyramid for more detail
To learn more about levels of evidence, click on the links below:
Use the arrows at the right and left of the box below to click through and see the characteristics of a number of different study types from the levels of evidence pyramid.
Use your PICO elements to create search terms. You might not include every element in your search, for example an outcome can sometimes be difficult to define.
The next step is to consider alternative terms that authors might use, for example synonyms, or medical terms. A table can be a useful way of recording these.
|Adults over 60||30 minutes of daily exercise||No exercise||Reduce heart attack risk|
Now you can use Boolean operators to group the terms together, and use search tips such as phrase searching and truncation:
(elderly OR aged OR geriatric) AND ("physical activit*" OR "aerobic training" OR "exercise*") AND ("cardiac arrest*" OR "heart attack*" OR "myocardial infarction*")
The library has many databases you can search in, depending on what level of evidence you need. Some of these databases allow you to filter results according to evidence type.
When you have found the articles and information, you will need to evaluate it for validity, and risk of bias. How you do this will depend on whether you are appraising primary or secondary research, and the study type, but there are common elements to consider. The CRAAP test is a good way to evaluate articles. A lot of what you need to appraise articles will be in the Methods section. Keep in mind evaluating articles is a skill that can take a while to learn, so if you need guidance, contact the library.
If you are interested in finding out more, the following article is old, but has some great questions to ask yourself when reading primary research, and is easy to read.
This is another older paper by the same author that describes in more detail how to appraise secondary research.
The article below has been annotated using the CRAAP test from above. Scroll through and hover the mouse over the highlights to see the types of things to consider when evaluating an article.
Han, X., Eggett, D. L., & Parker, T. L. (2018). Evaluation of the health benefits of a multivitamin, multimineral, herbal, essential oil-infused supplement: A pilot trial. Journal of Dietary Supplements, 15(2), 153-160. https://doi.org/10.1080/19390211.2017.1331943
There are a number of tools and checklists researchers use to appraise studies that you can look at for a more detailed way of evaluation..
Useful article on appraising qualitative research articles:
The following PDFs are examples of using the CASP Randomised controlled trial to appraise an article. Look at the article yourself, fill in the checklist, then see how your appraisal compared to our librarian's!
Seers, K., Crichton, N., Martin, J., Coulson, K., & Carroll, D. (2008). A randomised controlled trial to assess the effectiveness of a single session of nurse administered massage for short term relief of chronic non-malignant pain. BMC Nursing, 7(10). https://doi.org/10.1186/1472-6955-7-10
Critical Appraisal Skills Programme. (2019). CASP randomised controlled trials checklist. https://casp-uk.b-cdn.net/wp-content/uploads/2020/10/CASP_RCT_Checklist_PDF_Fillable_Form.pdf
In this stage, you decide if the evidence you have collected is suitable for your clinical situation.
You also need to consider the other two areas of evidence based practice: clinical expertise and patient values.
Sometimes you are not certain of the right thing to do even after looking at the evidence. To help you decide, you can:
The final step is to reflect on your practice and consider strengths, weakness and where you need to improve.
Consider how you applied the evidence, whether what you implemented was effective, and was the outcome satisfactory for the patient.
The Centre promotes evidence-based health care and provide support and resources to anyone who wants to make use of them. Includes the EBM Toolbox, an assortment of materials which are very useful for practitioners of EBM, and EBM Teaching Materials, including PowerPoint presentations.
Includes many resources for practicing and teaching EBM
Contains links to recent publications published by the ARCHE team.
From Duke University Medical Center Library and University of North Carolina at Chapel Hill Health Sciences Library.
Levels of evidence and evidence grading can be used to indicate the certainty of evidence - if the evidence is strong and can be used to support or change practice, or if the evidence is weak and should be used with caution.
Joanna Briggs Institute. (2013). JBI levels of evidence. JBI. https://jbi.global/sites/default/files/2019-05/JBI-Levels-of-evidence_2014_0.pdf
Joanna Briggs Institute Levels of Evidence and Grades of Recommendation Working Party. (2014). Supporting document for the Joanna Briggs Institute levels of evidence and grades of recommendation. JBI. https://jbi.global/sites/default/files/2019-05/JBI%20Levels%20of%20Evidence%20Supporting%20Documents-v2.pdf
Nice tabular summary of the JBI levels of evidence:
JBI, & University of Adelaide. (2021). JBI EBP database guide. Wolters Kluwer. https://ospguides.ovid.com/OSPguides/jbidb.htm
National Health and Medical Research Council. (2019). NHMRC levels of evidence and grades for recommendations for developers of guidelines. NHMRC: Building a healthy Australia. https://www.nhmrc.gov.au/sites/default/files/images/NHMRC%20Levels%20and%20Grades%20(2009).pdf
National Institute of Clinical Studies. (2009). Appendix F: Levels of evidence and recommendation grading. In Emergency Department stroke and transient ischaemic attack care bundle: Information and implementation package. NHMRC. https://www.nhmrc.gov.au/sites/default/files/images/appendix-f-levels-of-evidence.pdf