Today, my professional association, the British Veterinary Association, has launched their Manifesto for Evidence Based Veterinary Medicine (or EBVM, because I’m on a tight word count!). And here at VetHelpDirect, we’re really proud to be listed among the organisations to endorse that – because we think that EBVM is the best and only way we’re going to be able to improve health and welfare outcomes for our patients and our clients (animal owners, perhaps like you). So in this blog, the first in a series on EBVM, we’re going to look at what EBVM is and why it’s so important.

What is EBVM?

Basically, it’s making sure that whatever we do when we’re treating your animals, that we’re using the most accurate and up to date evidence that there is. That we’re not relying on “gut instinct” or “ancient wisdom”, and we’re not “doing it because that’s how we’ve always done it”, or because it’s currently fashionable, or worst of all only because it’s profitable.

Why is that important?

So that we can make sure that the advice and treatment we give has the very best chance of being effective and not harmful.

But surely if it works that’s all that matters?

But here’s the problem – how do we know that it works? I might think it does, and you might think it does – but that doesn’t prove anything. The human brain is the most complicated structure in the known universe, and the mind is even more complicated than that. As a result, a lot of what we think we see or understand isn’t actually entirely true. 

The brain takes shortcuts all the time – and a lot of the time, they’re right. But they can also be very, very misleading. We call these mental shortcuts “cognitive biases” (and there’s a fantastic infographic on some of the more important ones here). And if you think you don’t have any – that’s an example of both Naive Realism and the Dunning-Kruger Effect. 

We all have these biases

Which is why “I used this medicine and the patient got better” isn’t a reliable indicator that it works. The most famous example is the one from 1820s France where researcher Pierre Louis proved that the standard medical treatment of the age (bleeding) was harming patients, not helping them. All the thousands of doctors who were convinced they were saving their patients had, in fact, been absolutely wrong, and had probably killed a significant number of them.

Particularly important ones in veterinary medicine include:

The Bandwagon Effect

The more people use the drug, the better it must be… Or perhaps the company was just better at marketing it?

The Availability Heuristic

We’re likely to rely more on the most immediate example – so if I’ve just read an article about a particular illness, I’m more likely to diagnose it in my next patient.

The Anchoring Effect

If I happened see a rare disease for the first time in a rare breed of cat, I’m likely to think that the disease is more common in that breed – even if it’s just coincidence.

Confirmation Bias

Evidence that supports something we already believe is given a higher weighting when making a decision. This explains why very weak studies in support of a treatment tend to be used to support it by those who are already using that treatment.

The Sunk Cost Fallacy

The more effort, time or money we’ve put into something, the more we’re likely to persist in sticking with it. So if my practice has just bought a £20,000 machine, I’m more likely to believe that it works.

Authority Bias

We like to trust in experts – even if the evidence clearly shows that they’re wrong.

The Dunning Kruger Effect

The less you know about a subject, the more certain you’re likely to be about it. As we learn more, we realise how little we actually know! This, by the way, is why vets tend to be very cautious professionally (with lots of phrases like “usually” and “in general”), but are often very confident in unrelated areas where we aren’t necessarily that competent.

Blindspot Bias

We tend to believe that we don’t have these biases…

As you’ll see, many of these biases have a basis in reality. But collectively, they can really distort our understanding of what’s REALLY going on!

So how do we minimise that?

Big data

The more evidence we have the more certain we can be of the results.

Good statistics

Statistics are a fantastic tool for determining if there really is a link between two factors or not – did the group getting the experimental drug REALLY get better faster or not? Or was that our biases talking? (See also hydroxychloroquine…)

Controlled trials

By making sure that the experimental group is matched with a group receiving normal care, we can be sure that it was the experimental treatment that made the difference, not some other factor.

Blinded trials

We’re all biased! But if the researcher and the animal owners don’t know which animals got the treatment and which didn’t, those biases don’t matter.

Peer review

Any study potentially has flaws that the authors missed. Peer review means that they’re checked and obvious errors are found.


And then, ideally, the trial is run again, to make sure the link is genuine and not a random chance fluke!


Ultimately, all the trials are combined and statistically analysed, again, to rule out a chance fluke.

What is the “EBVM Manifesto”?

As a profession, we’ve been a bit stuck in a rut on this one. There isn’t really enough money in the veterinary world to pay for a lot of really big, good quality trials by commercial organisations, and so we’ve largely been making do with lower quality evidence – case reports, for example.

There’s also something of a backlash from a small minority in the profession who don’t see any reason not to continue the (highly profitable) unproven remedies they personally are fond of. This is particularly a problem in the “alternative” and “holistic” sectors, but is a trap we’re all at risk of falling into.

So, the BVA’s manifesto is part warning, to use the evidence better, and part call-to-arms, to generate more and better data – and then analyse it properly.

Evidence-based veterinary medicine manifesto for better health
  • “Vet professionals are the advocates of animals – patients not clients are the primary focus of what we do
  • Expand the role of health professionals, policy makers and clients in research
  • Increase awareness and the systematic use of existing evidence
  • Make research evidence relevant, replicable and accessible to end users
  • Reduce questionable research practices, bias, and conflicts of interests
  • Ensure drug and device regulation happens and is robust, transparent, and independent
  • Produce better usable clinical guidelines
  • Support innovation, quality improvement, and safety through the better use of real world data
  • Educate professionals, policy makers, and the public in evidence-based healthcare to enable informed decisions
  • Identify and encourage the current and next generation of leaders in evidence-based medicine”

BVA, 2020

You can read more about the project here.

So now’s the time for us all – vets, researchers, allied professionals and animal owners – to do something about this. Let’s make sure we support those people generating AND using real evidence. If we’re doing something that isn’t backed up – let’s gather the evidence to check that it works. And if it doesn’t work – let’s stop using it! 

And above all – let’s stop arguing on the basis of our opinions and see what really works… Because if there’s anything you learn when you start doing real research, it’s that unless constantly re-examined and calibrated to the real world, our opinions are very rarely accurate or reliable.