What is clinical and statistical significance in nursing evidence based practice?

Sample Question

Not all EBP projects result in statistically significant results. Define clinical significance, and explain the difference between clinical and statistical significance. How can you use clinical significance to support positive outcomes in your project?

Sample Answer

For successful implementation of evidence based practice, understanding and interpretation of the research is essential. For this reason, it is important to understand the difference between statistical significance and clinical significance. Statistically significant result implies a relationship or a difference between the variables that was not solely caused by normal variation or chance.  In this regard, statistical significance as a parameter in evidence based practice shows the extent or the likelihood that finding from research is true and does not occur by a chance (Heavey, 2015).

The probability value (p value) is used to show the chance of the randomness of a particular result occurring but not the actual variance between the variables under question.  In research analysis, results are statistically significant when the probability value generated during the analysis is less that the certainty level needed by a researcher. In research studies including evidence based practice, researchers normally set probability values at 0.05, which imply a chance of 5% that the result was not caused by a probability and a 95% certainty that there exist an actual relationship between the variables analyzed in the study (Heavey, 2015). 

Clinical significance is essentially a subjective interpretation of research findings as meaningful for patient under care, and therefore likely to influence the behavior of healthcare provider (Heavey, 2015). A clinically significant result occurs when medical experts believe that the finding is considerable enough to be medically crucial and hence be applied as a guide in provision of care to patients.

In evidence based research practice, statistical significance must always be determined before determination of clinical significance. However, clinical significance is usually a subjective evaluation and cannot be established by a single experiential test.  I can use clinical significance to support positive outcomes in my project outcome by ensuring that the result is statistically significant. This is due to the fact that majority of statistically significant findings are normally have clinical significance.


Heavey, E.(2015). Differentiating statistical significance and clinical significance.  American Nurse Today, 10(5): 26-28. Available from https://www.brockport.edu/daily_eagle/doc/2015-04/item_8038_7659.pdf