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Evidence Based Practice (EBP) Research

Introduction to the EBP process including resources and instruction.

How Treatment Effect Heterogeneity Works [NEJM]

Understanding Research: Resources

When appraising research, keep the following three criteria in mind:

Quality 
Trials that are randomized and double blind, to avoid selection and observer bias, and where we know what happened to most of the subjects in the trial.

Validity
Trials that mimic clinical practice, or could be used in clinical practice, and with outcomes that make sense. For instance, in chronic disorders we want long-term, not short-term trials. We are [also] ... interested in outcomes that are large, useful, and statistically very significant (p < 0.01, a 1 in 100 chance of being wrong).

Size
Trials (or collections of trials) that have large numbers of patients, to avoid being wrong because of the random play of chance. For instance, to be sure that a number needed to treat (NNT) of 2.5 is really between 2 and 3, we need results from about 500 patients. If that NNT is above 5, we need data from thousands of patients.

These are the criteria on which we should judge evidence. For it to be strong evidence, it has to fulfill the requirements of all three criteria.

Source:  Critical Appraisal. Bandolier.

Dombrowsky T. (2023). Linear regression: A beginner's guide for nursing research. Nursing, 53(9), 56–60. https://pubmed.ncbi.nlm.nih.gov/37616410/

Some points to consider when evaluating information on the Internet or in print.

If a claim conflicts with...

  • our background information, we have good reason to doubt the claim.
  • other claims we have good reason to accept, we have good grounds for doubting it.
  • expert opinion, we have good reason to doubt it.

Avoid confirmation bias:

  • It's reasonable to accept the evidence provided by personal experience if there's no reason to doubt it.
  • Common mistakes in evaluating claims are resisting contrary evidence, looking for confirming evidence, and preferring available evidence. 

Source: Vaughn, L. (2019). The power of critical thinking (6th ed., Chapter 4). Oxford University Press.

 

Educational Resources:

Avoid making big decisions based on one study as there is always some uncertainty in science. 

Worsham, C. and Jena, A., 2021. Evidence-Based Medicine Shouldn’t Mean Treating Everyone the Same. [online] Harvard Business Review. Available at: <https://hbr.org/2019/01/the-art-of-evidence-based-medicine> Accessed 29 September 2021

A Systematic Review vs. Meta-Analysis vs. Literature Review vs. Scoping Review. Scribbr, 2022.