Give me a minute, and I’ll get to the cows and sharks.

You would be surprised at how few doctors are familiar with even the most basic statistics. Medical journal articles often have statistical errors that are missed by manuscript peer reviewers and readers alike.

Most medical students have taken a course in statistics, but it is usually taught in the first or second year of school. By the time they start residency training when they could use the information, they have forgotten most of it. Statistics should be taught during the clinical years of medical school and reinforced throughout residency training.

Hospital administrators are even more clueless than physicians. I have blogged before about the irrational responses of administrators to miniscule changes in poorly constructed surveys of patient satisfaction. When scores go down by insignificant percentages, all hell breaks loose with task forces, ad hoc committees, and browbeating of staff.

Here’s a fun exercise involving statistics. It’s OK. No formulas will be discussed.

Which animals kill more people per year in the United States, cows or great white sharks?

Although a German tourist was recently killed by a shark in Hawaiian waters, the answer is overwhelmingly “cows.”

How can this be? You rarely hear about a cow killing a human, but it happens about 20 times every year. Between 2003 and 2008, 108 people in the United States died from injuries caused by cattle, according to the Centers for Disease Control and Prevention. That’s 27 times the whopping 4 people killed in shark attacks in the United States during the same time period, according to the International Shark Attack File.

Guess how many cows there are in the US.

According to the Drovers Cattle Network, there were 96.5 million head of cattle here as of mid-2013. The cattle population dwarfs the number of great white sharks. The New Ecologist estimates that the number of great whites in the entire world is about 3500.

The Guardian recently reported that there have been 1,085 recorded shark attacks in the US since the year 1670 for an average of only 3.5 shark attacks each year for the last 342 years.

Although not as dramatic or as newsworthy as a shark attack, it is far more likely that a person will be killed by a cow than a great white shark.

So keep your statistical radar turned on. Be skeptical.

And if you see an udder in the water, get to shore as fast as you can.

Skeptical Scalpel is a recently retired surgeon and was a surgical department chairman and residency program director for many years. He is board-certified in general surgery and a surgical sub-specialty and has re-certified in both several times. For the last three years, he has been blogging at and tweeting as @SkepticScalpel. His blog averages over 1000 page views per day, and he has over 6900 followers on Twitter.