Apply Now

What is Evidence Based Medicine?

01/01/70 | 6 MIN READ


Learn about evidence based medicine, its applications, and why you should care.

Cause and Effect

Let’s say that you had a 103.4 degree fever. You go to the doctor and get prescribed some penicillin. A couple of days later, your fever is now lowered to 100.2 degrees. So, did the penicillin cure your disease? The answer is dependent on the case. The penicillin may have taken care of reducing your fever, or your fever might have gone down after a couple of days anyway.

Now, let’s put a little bit of variance on this scenario. Imagine you had all of the above happen to you, but then 4 days later you receive a positive COVID-19 test. So did the penicillin cure the COVID-19 virus? Most likely not. Penicillin is used for bacterial infections, and the coronavirus is just as the name states, a virus. 

These types of scenarios illustrate the challenges that come along with evidence based medicine, and why it is important. We will go more in depth as to why this is so throughout the article. If you want to learn more about COVID-19 and its effect on the medical industry, check out this article


What is Evidence-Based Medicine?

Here is a great definition from Masic: “the conscientious, explicit, judicious, and reasonable use of modern, best evidence in making decisions about the care of individual patients.” 

EBM Venn Diagram


This article will be emphasizing the science part of this Evidence Based Medicine (EBM) venn-diagram, but clinical judgement and patient values are other important parts. An example of clinical judgement is a doctor avoiding prescribing a medication that might clash with another medication the patient is taking. It requires listening to the patient as well as general medical knowledge. Patient values are important when making medical decisions because it allows an individualized approach.

EBM also works to use high quality clinical research while making clinical decisions. This allows the most informed decision possible. Keeping up to date with recent clinical studies allows one to use on-going, problem-based learning.


History of Medicine

Understanding the past of medicine is essential to understanding our future. In the not-so-distant past, bloodletting was a common “cure” for many diseases. This was not beneficial to the patient, and we have moved on from this practice.

Putting history in perspective, we can ask ourselves what types of medical practices will be obsolete in the not so distant future. Only time will tell!

In terms of medical training, Germany was a major global leader in the field from the 19th to 20th centuries. Their medical schools were filled with forward-thinkers that attempted solving the world's medical problems, like Robert Koc. He was a german physician that helped to develop the field of bacteriology.

If you lived during the 19th century in the US, you would most likely want a doctor that was trained in Germany to look over your medical needs. This changed in 1910, when the Flexner Report set standards for US doctors and hospitals. This led to the creation of university medical programs, like the ones at Johns Hopkins and Harvard. From that point forward, the United States was the major global leader in medicine and medical advancements.

In 1993, the Cochrane Collaboration created systematic reviews and guidelines. The collaboration did this to create evidence informed healthcare that was both effective and sustainable. They were also committed to transparency, including encouraging non commercial funding for many new projects. There have been multiple other guidelines created, but the Cochrane is most notable, especially now that it has been endorsed by the World Health Organization (WHO).


5 Steps to EBM

Below you will read about the 5 steps to EBM. Each step is aiming to get you thinking about the validity of presented evidence. 

  1. Translation of uncertainty to an answerable question

An example of this would be a question like, “What are the odds of success with one treatment versus another?” These questions allow concrete answers, which are easier to research.

  1. Systematic retrieval of the best evidence available

You want to be sure to use the tools and information that best suits your question. Is your evidence both recent and reliable?

  1. Critical appraisal of evidence for validity, clinical relevance, and applicability

This is another step of examining your revidence. Is it both internally and externally valid? Internally valid means that the study was performed with a clear cause and effect. Is there a strong association within the study’s evidence? Externally valid means that the study is also applicable to your individual question. Will this evidence help solve the issue, or is it only slightly related?

  1. Application of results in practice

This step is making sure that your results and findings are applicable to the entire population you are trying to help. It is best to ask questions such as, are results valid in one country/group and not another?

  1. Evaluation of performance

This step is all about check-ins. The process of EBM should be continual and ongoing. Checking in with patients to make sure the solution is permanent is important to improving their experience. Keeping a log or journal is a great way to keep track of these findings.


Types of Studies

Types of Studies

Check out the graphic above to understand the validity of some common sources of evidence. The lowest level of confidence is someone’s editorial of opinion. This is usually just an idea that someone has put out there, with no study attached. These can be a good reference for future studies, but not used as actual clinical evidence. 

A little bit further up the list we have case control studies. These studies monitor individuals with certain conditions. These are not extremely reliable because there is not a large sample size. But, they can be helpful for studies involving rare diseases. 

The study with the highest level of evidence is a meta-analysis. A meta-analysis combines the results of a number of studies. This allows the largest sample size and the most confidence for reviewers.

Each study has a different confidence level as well. Level I studies contain at least one randomized controlled trial. Examples of studies with Level III confidence are opinions or editorials. This means the higher the level, the lower the confidence. Learn more about types of clinical studies in this article about vaccine development.


Systematic Review

Here is the dictionary definition of systematic review:

“a review of the evidence on a clearly formulated question that uses systematic and explicit methods to identify, select and critically appraise relevant primary research, and to extract and analyze data from the studies that are included in the review.”

Essentially it is gathering data and then analyzing it in a predetermined process, with the focus on removing as much bias as possible. That being said, some types of studies, specifically observational can breed bias because of their very nature. 

The Cochrane Collaboration created a guideline for systematic review in order to increase their rigor and decrease their bias. One of the best ways to reduce bias is to use blinding while collecting the data and administering medicine. Systematic review is directly linked to Evidence Based Medicine. Creating products and giving diagnoses using the most relevant and accurate data is essential to EBM. Studies with systematic review are some of the most relevant and accurate. 



GRADE stands for Grading of Recommendations, Assessment, Development, and Evaluations.  GRADE was originally developed independently of Cochrane, but was later incorporated as a part of their assessing studies initiative. GRADE is technically a subjective process, which sounds biased in its nature. But, GRADE uses multiple subjective observers and compares their findings. This is what makes it objective in the long run. Learn more about GRADE from their webpage here.

GRADE accounts for various categories of bias, including imprecision, indirectness, and inconsistency. Each of these factors can contribute to the biasing and invalidation of a study.

GRADE will eventually give a categorization of the evidence. The categories range from High Quality Evidence, to Very Low Quality Evidence.


Other Methods and Approaches

There are other systematic review methods that do not involve GRADE or the Cochrane Collaboration. One example is the US Preventive Services Task Force. Check out the link to learn more. The USPSTF classifies research into Levels A, B, C, D, and I. Level I represents uncertain evidence while Level A represents fair evidence that the benefits outweigh the risks. 


Criticisms of EBM

Here are a few criticisms of Evidence Based Medicine:

  • Demand for EBM outweighs the supply
  • Randomized controlled trials may not be universally relevant
  • Publication bias or conflict of interest
  • Lag time between publication and proper application

Obviously, Evidence Based Medicine has a long way to go before it is perfect. But, for the time being, it is a great strategy to ensure proper patient and clinical care.

Frequently Asked Questions

Q: How do you balance the science, clinical judgement, and patient values?

A: This will be very situational and depends on the problem and the patients themselves. It will also depend on whether or not the doctor is open to changing and open to looking at new evidence.

Q: Is there a difference between how industry and clinicians use evidence-based medicine? 

A: Clinicians use the 5 steps of medicine mainly. Industry professionals will be more about analyzing the larger group. Industry professionals will have to do more research on studies when creating products as opposed to when treating patients.

Q: How can one learn more about EBM? 

A: Check out the USPSTF and Cochrane Collaboration websites. There you can do a deep dive on EBM guidelines and procedures. 

This information comes from a talk with Dave Miller, ScienceDocs consultant, in partnership with University Lab Partners. Watch the full webinar here.

Dr. Miller is a veterinarian with a PhD in Clinical Science. His PhD studies emphasized the epidemiology of agent transmission, diagnostic testing, and One Health. He has advanced clinical specializations in animal welfare (Diplomate of the American College of Animal Welfare) and zoological medicine (Diplomate of the American College of Zoological Medicine), as well as experience in a variety of laboratory, research, regulatory, exhibition, and other clinical settings.

If you want to learn about business planning, check out this article from ULP about Creating an Effective Business Continuity Plan.

Be sure to subscribe to the ULP Youtube Channel to never miss another webinar, and connect with us on LinkedIn to stay in the loop!

Free Resource

The Ultimate Guide to Wet Lab Incubators

Download The Ultimate Guide to Wet Lab Incubators in Southern California, a handbook to assist life science start-ups through the entire decision-making process to find wet lab space.


Fill out the form below to download the Ultimate Guide

Apply for residency today

Do you have a great company in the bioscience or medtech industry? Do you need wet-lab and/or fabrication space to develop and test your product?