We need to live in an evidence-based reality, but what is “evidence”?

I went to visit my mother over the weekend. She and my little sister have birthdays on consecutive days, so it was a good time to visit. Among the many “rituals” that my mother has when we (my younger brother and I) visit is to introduce us to her many friends. Let me tell you, that woman has friends.

One such friend, whom I’ll call Betty, was sitting with mom in the kitchen when I walked in from outside. My siblings and I had gone to the local public library to access the internet. So I walked in, mom introduced me to Betty, and we got to talking about mundane things like how long we’d be there, how the visit was going, etc. Then mom asked me if I had heard of “the city in the clouds.” Betty immediately jumped in. “It’s those clouds that jet planes drop on us like viruses.”

I was not prepared for that kind of anarchy. My natural response was to shake my head in disagreement almost immediately.

“The government wants to control us and depopulate us,” she continued.

“Well, they’re doing a horrible job at it,” I replied. “Besides, it’s not true…”

“Oh, it’s true!” she interrupted. “I have sources that have confirmed this to me.”

“It’s not true because contrails are the result of the condensation of air behind the plane as the plane’s vortex off the wings mixes the air,” I continued. “They’re just clouds.”

To this, she began shaking her head as well. I knew then that it was going to be a battle of wills, and I didn’t have the time. I was there to celebrate with my siblings and mother, not to debate reality. “It’s mind control.”

“It’s not. We’ve looked into this, and it’s not.” To that, I said it was nice to meet her and walked back out to the car to return to the library with my siblings. She and mom stayed in the kitchen.

That little exchange got me to think about the discussions I’ve had and will be having in the future as I work toward the DrPH and even once I get it. As you may or may not know, some of my biggest arguments online and in person have been with anti-science people in general and anti-vaccine people in particular. Some of the things they have said and written are flat-out wrong, especially in light of all the evidence we have about vaccines.

But here’s the thing. They also have “evidence.” They have physicians and scientists on their side (at least people with academic degrees identifying them as such). One well-known British physician was found to have conducted a fraudulent study that ended in the decline of MMR vaccine uptake in Europe and North America out of fear of the vaccine causing autism. And there is also this neurosurgeon who repeats all sorts of anti-vaccine talking points. These two men are medically-trained people who studied enough to receive medical degrees. Is their “evidence” as valid as mine, a lowly epidemiologist (and DrPH candidate)?

So one of the things that I will take on over the next few months on this blog is how to measure evidence, how to tell what is sound evidence and what isn’t. I’ll start off with a quick primer on how to read a “study” and understand its findings and shortcomings. Then I’ll explain to you why a single study, or even a handful of studies, is not enough to reach a conclusion, touching upon the “correlation is not causation” concept. And then I’ll finally explain how reality dictates evidence and vice-versa.

No, this is not the return of the “Epi Night School”, but it’s close.

I'm a doctoral candidate in the Doctor of Public Health program at the Johns Hopkins University Bloomberg School of Public Health. All opinions posted here are my own, of course, and they do not necessarily reflect the opinions of my school, employers, friends, family, etc. Feel free to follow me on Twitter: @EpiRen