Ken Rothman, DrPH on ambition, writing, and detainment by the Colombian police

Ken Rothman, DrPH is arguably one of the most influential living epidemiologists. Ken has been in the field for almost 50 years, conducting research, writing, and teaching. He co-authors two of the most used textbooks in epidemiology: Modern Epidemiology and Epidemiology: an Introduction. He is the founding editor of Epidemiology, a leading journal in our field. He talks with me about his ambition, his status as a 'legend' in the field (spoiler alert: he says that is patently false), writing, an award lecture gone awry, sailing, being detained by the Colombian police, "Baby Rothman," and much more!

Transcript

Lisa Bodnar:

(silence) Hi, Ken.

Ken Rothman:

Hi, Lisa.

Lisa Bodnar:

Cheers.

Ken Rothman:

Cheers to you.

Lisa Bodnar:

Last time I saw you in person. Do you remember when that was?

Ken Rothman:

Not long before the pandemic arrived, at a little bar in Downtown Boston.

Lisa Bodnar:

There were a lot of BU folks there, and it was such a fun night, and I think it was one of my last outings pre-pandemic.

Ken Rothman:

Yeah, same for me.

Lisa Bodnar:

It's been a bananas year. And you're back to traveling.

Ken Rothman:

Well, I made one trip to see friends and family. I'm old, so I got vaccinated early. I felt like I had made a miscalculation, because all along I've been planning I'd get vaccinated, get my immunity, and then I'd be able to travel. And then when the time came and I had booked my tickets and everything, there were these CDC announcements about how you shouldn't travel even if you're vaccinated, which I confess I did not understand. And in the end I traveled anyway.

Lisa Bodnar:

Well, were they saying at the time non-essential travel was not allowed? but I think in your case it was kind of essential, don't you think?

Ken Rothman:

You know what? That's a good explanation. Thank you.

Lisa Bodnar:

You hadn't seen your daughter or your grandkids in over a year.

Ken Rothman:

That's true. And my sister and so on, yeah.

Lisa Bodnar:

So thanks for being on my show. When I first reached out to you and we had a chat about your being on, we talked for an hour, and then I was like, "What do you think? Would you want to be on my show?" He said, "No, not really, but I'll do it if you want." So thank you.

Ken Rothman:

You're welcome. And here we are, so you're very persuasive.

Lisa Bodnar:

Yeah, I suppose so. Okay, let me dive in. When you got into epidemiology, what was your ambition at the time? And how did that evolve as your career got further?

Ken Rothman:

Well, my ambition was to find a job that I didn't mind. If I had heard of epidemiology earlier in life, I would have chosen it as a path. I think nowadays, even before the pandemic people were more likely to have heard of epidemiology, and now that there's been the pandemic a lot more have. But in those days it was something that never reached my level of consciousness. And when I discovered epidemiology, I had already made other choices and gone off in different directions. But when I discovered it, I thought, "Oh yeah, this is something I could enjoy doing. And remarkably, they might even pay me to do it."

Ken Rothman:

My ambition... I think it was it's pretty mundane. It was just, try not to screw up. Do a good job. Watch out where you step. You might step in a hole. That kind of thing. I mean, I learned very early... When I was a student, I learned how you can mess up without ever knowing it, and I think you can do it in all innocence. As a student, I had read a paper just published about two different causes of mouth cancer, tobacco smoking and alcohol drinking. I thought, "Well, this is really interesting." And it illustrated two factors that everyone presumed, and I think rightly so, were both causes, and yet the effect of each was confounded by the other one, because the exposures were correlated.

Ken Rothman:

And in addition, there was another element that wasn't addressed in the paper I read, which was that there could be an interaction, what I would call today a biological interaction, what in those days people might have referred to just as interaction without qualification. And I, thought, "Well, this is something else that could be explored," and it opened me up to thinking about methods a lot, which I hadn't... I was just a student in those days and just trying to learn what they were teaching. So the thing was, it required a different analysis. And I had to figure out, "How do I get these data? How do I collaborate with these folks who've published this paper." It was a very nice paper, but just they hadn't thought about what I was thinking about.

Ken Rothman:

So I went to department head in Harvard. It was Brian MacMahon, an eminent epidemiologist. And I said, "Can you tell me, what's the proper thing to do here if I want to use their data?" He said, "Well, you want to collaborate with them, so you're going to have to see if they're willing to do it. You have to ask. And I suggest you write to the senior author of the paper." I don't know if he said senior author. Ge probably said lead author. So I wrote to the lead author of the paper, and he was very happy to collaborate, and he sent tables, and we conducted analysis together. We wrote up a manuscript. He seemed quite happy with it, and we published it.

Ken Rothman:

The man who was unhappy with it was the third author of that paper who didn't mean a thing to me. I was a student. But he was a luminary in public health. And he was really incensed that I hadn't addressed him instead of this guy, who was his student, as it turned out, doing his doctoral thesis. So I made a lifelong enemy.

Lisa Bodnar:

Really?

Ken Rothman:

Oh yeah. He did everything he could to screw me up when our paths crossed after that. So this is a good lesson. This academic world, it can be pretty treacherous. What can I say? I mean, I wouldn't have done that if I had known it would have incensed him, but I had never heard of him before. And that was the problem. I should have heard of him, according to him.

Lisa Bodnar:

When people say that you are this legend in our field or the father of modern epidemiology, what do you think?

Ken Rothman:

Well, I think it certainly doesn't apply to me and it's not true and it's a mistake. I can do a couple things okay, and there are a lot of things I don't do as well as other people in the field, and I'm happy to acknowledge that.

Lisa Bodnar:

I mean, you're a super, super humble guy. I know that. But given objectively all that you've done in the field, isn't there some truth to it?

Ken Rothman:

As I say, I've just been trying to avoid stepping in holes and moving on. I don't know. I mean, I had good teachers and I learned a lot from them. And I enjoy writing, so I spend a lot of time working on writing to make it interesting to read. Don't always succeed in that, but sometimes I do, so people occasionally like to read some of this stuff. And some people don't. There are Amazon reviews that talk about how terrible the writing is. And sometimes I read those and I think, "Oh, I remember the days before Amazon."

Lisa Bodnar:

Right. One of the papers that you wrote that I really love is one I don't know if you remember, but you wrote it when you were editor in chief of Epidemiology, and it was called How to write for Epidemiology. Do you remember this?

Ken Rothman:

Oh yeah, I remember that. I wrote that as a way of, first of all, making life a little bit easier once I became editor, to tell people what I was hoping to get and also give them some suggestions about how to make their papers better. I had spent a lot of time by then as an editor and a writer, and those were my tips. The most important tip was how to draw a figure for publication, because most people just get that wrong. They take the output from some canned program designed by a programmer who never published a paper with a figure in it, and then they submit it, or they use it in a slide at a meeting, and that doesn't work.

Lisa Bodnar:

What do you tell people to do instead?

Ken Rothman:

Well, the main thing is, usually you can't read the slides, the labels on the axes, value labels. The lines are too thin usually. Need to be bold. It needs to give you a visual impact. You shouldn't have to scrutinize it and study it to figure out what's going on.

Lisa Bodnar:

Two of the things that you wrote in that paper have become huge pet peeves of mine in other people's writing, and they are using the word utilize instead of use and saying prior to when you can just say before.

Ken Rothman:

Those are two things that bother me too. Prior to more than utilize, but yeah, simple short words are better. There's a tendency, a natural tendency, to emulate your peers when you're a student, and you look and see what people are doing, and that's what promulgates stuffy writing in part.

Ken Rothman:

And also use of techniques and methods that should have been abandoned, like significance testing. I think that's probably the methodologic issue that has bothered me the most, because it was so clearly wrong. When I first learned about significance testing, it looked wrong to me. And yet everybody did it, kind of had to do it. But very early in my career, I started to criticize it. That was not a novel thing to do, because criticism of significance testing had been around for a century. I've been writing on that topic ever since. And that was one of the reasons to write a book, to start a journal, and to continue as a teacher.

Ken Rothman:

I think significance testing has killed people, because it's so common that people come to the diametrically opposite of the correct conclusion because they base their inference on significance tests. Exposures or treatments that have good benefit have been judged to be without any effect because the judgment was based on a significance test. And in the other direction, things that were judged to have an important effect had trivial effects, because again the interpretation was based on significance testing rather than on a judgment about the size of an effect. So you can see mistakes in both directions that are avoidable. And you don't have to go very far to see people pointing out these kinds of mistakes all the time, but a good part of the world is still oblivious.

Ken Rothman:

But things have changed, and I take some heart from that. I think early on, I thought, "Well, this'll never change." And I would have discussions with friends like Charlie Poole and Steve Lanes and others who were concerned about it, but there was some cynicism that maybe it'll never change at all. And I think it has. It has gotten better in epidemiology, and maybe some other fields are beginning to pay attention.

Lisa Bodnar:

I want to ask you about a couple of lectures that you've given, the first lecture you ever gave, and then the John Cassle Memorial Lecture.

Ken Rothman:

The first lecture that I remember was... It was a lecture in an introductory course with basically the entire master's program attending, because everyone had to take epidemiology. This was just one slot in the introductory course. And I sweated over this for weeks and months. I ended up thinking that I was going to be so nervous that I would fall off the stage. So I wrote it out word for word, and then I think I nearly memorized it. But I wrote it with some keywords and tried to figure out how to deliver it so it seemed normal. I don't know how it actually seemed. But I remember a great feeling of relief when that ended.

Lisa Bodnar:

Yeah, no doubt. That's scary.

Ken Rothman:

Doesn't every academician who ends up in a teaching position where you might have big classes go through the same thing?

Lisa Bodnar:

Think absolutely.

Ken Rothman:

It bothered me. I still got nervous when I give a talk.

Lisa Bodnar:

Do I? I do too.

Ken Rothman:

Yeah, absolutely. Well, the Cassle lecture was another example. So that was a big lecture, an invited talk among epidemiologists. It was at Snowbird. It was mid '90s, 1995 I think.

Lisa Bodnar:

Snowbird is in Utah?

Ken Rothman:

Snowbird is in Utah. It's ski resort. So we're up in the mountains in June, start of summer, but in a ski village June isn't necessarily a warm season. Here I was, nervous about the talk. I had worked it a long time. And then turned out that the venue was not what I was imagining. They had put up one of these temporary structures, it was a tent basically, for the plenary sessions. It was just canvas. And the temperature was like 30 degrees that day when the sun was coming up over the mountains. But they were prepared to deal with the frigid temperature. They had these trucks with portable heaters and piped in hot air through these big vents that filled the tent with hot air.

Ken Rothman:

So that solved the heat problem, except that it created another problem, which was you couldn't hear a thing over the roar of these fans blowing the heat in. I imagine it was like 75 decibels or something like that background noise. That had me a little worried, but I thought, "Okay, so for 20 minutes or 30 minutes of the talk, I'll just shout." But then as the sun reached the crest of the ridge, direct sunlight started to shine on the tent. And that happened just before my talk. And suddenly the whole tent became very bright. And in particular you couldn't see the screen, so the slides were invisible. So you couldn't hear and couldn't see, but you had no choice but to go on. So I went up there, and I had my notes, and I put them on the lectern too late to realize that the lectern didn't have a lip on the bottom and it was quite slippery, and all my notes fell off and blew around the stage. And that's where I was on the Castle lecture.

Lisa Bodnar:

What do you think was the best piece of career advice you got?

Ken Rothman:

Gee, I don't know.

Lisa Bodnar:

Or do you have some career advice that you would give?

Ken Rothman:

Aside from being careful about stepping in holes? I don't really feel like I'm able to give career advice. I think I always encourage people to pursue their dreams, to follow a path that seems appealing to them, and to do their work well, but my experience is limited. I could have probably made better choices. Sure I could have. I think it's a little over-assertive to pretend that you know stuff, just because you survived a career or you got to be old, like the 100-year-old person advising you to smoke for 100 years because that's what he did. So I don't feel comfortable offering that kind of advice, but I made plenty of mistakes, so I would say avoid mistakes.

Ken Rothman:

There was a time when I was detained by the authorities in Medellín, Columbia for drug smuggling.

Lisa Bodnar:

Okay, what?

Ken Rothman:

Let me clarify. It was suspicion of drug smuggling.

Lisa Bodnar:

Okay, please, please explain.

Ken Rothman:

I was still a student in those days, and I had spent the previous summer in Medellín working on a public health project. While I was there, there was some community up in the Andes that was of interest, and there was some reason to do a follow-up study that involved taking environmental samples from this community, water samples and soil samples. It was my job to go and collect the samples. And I had just gotten married. My wife came along on this trip.

Ken Rothman:

And in preparation, I had gotten this big case with hinged top, and it was packed with layers and layers of empty polyethylene bottles, all numbered, to contain all the samples. So when I arrived in Medellín and went through customs and they took this case, they said, "What's in here?" And I said, "Oh, just empty bottles." So they opened it up and started to unpack all my neatly arranged bottles. They were all empty. There was a lot of discussion going on out of earshot of me. And then they let me repack them and they said, "You're okay."

Ken Rothman:

And then we went to a hotel where my wife experienced some allergic reaction. And after a day of suffering, she said, "We need to move to a different hotel." So we moved hotels. After a day or two, I got a message that my friend Jorge had been looking for me. The problem was, I didn't have a friend named Jorge in Medellín. And I said, "Oh well, it's just a mistake." Then the phone rang. It was in the evening, and it was the desk calling, and they said my friend Jorge was in the lobby. So I go downstairs and there are a couple of guys there, big guys, just wearing plain street clothes. And they spoke to me in my pretty elementary Spanish and said, did I fly a plane? I said no. They said they needed me to come in for questioning. I said, "Well, who are you?" And they take a little card out like a business card. And printed on it is two words, "policía secreta".

Lisa Bodnar:

Secret police?

Ken Rothman:

Secret police.

Lisa Bodnar:

Okay. Secret police.

Ken Rothman:

And that's all. I said, "What is this? Anybody could print one of these." They said, "This is like your FBI." And they said, "We have to take you in for questioning." And I was a little worried about this, because my concern was that these were just kidnappers, which wasn't out of the question in Medellín those days. So we ended up... My wife came downstairs, and they said we were going to walk to the place where we were going. And as soon as we stepped outside, we were surrounded by six or seven people, and they all had big bulges in their pockets, for weapons I presumed. And I had said that I wouldn't go unless the hotel bell boy would come with us.

Lisa Bodnar:

Poor guy.

Ken Rothman:

He was quaking. The entire hotel staff was quaking.

Ken Rothman:

But he did. He walked all the way. And then we finally got to some little army base or something. And they questioned me for a long time. Was someone else that they had confused me with. And I explained what I was doing. And they sent me back to the hotel under house arrest for half a day.

Lisa Bodnar:

Oh my gosh.

Ken Rothman:

And that was the end of it.

Lisa Bodnar:

Did it have to do with the bottles that you had brought?

Ken Rothman:

They had flagged me because of all these polyethylene bottles. Who comes into a country with 200 polyethylene bottles in a case, all empty and numbered? Then I think switching hotels probably raised their suspicions.

Lisa Bodnar:

Oh, right. I'm glad you told that. That's a great story. You must have been scared out of your mind.

Ken Rothman:

It became a great story after it ended.

Lisa Bodnar:

Yeah. Can I ask you about your adventures on the Charles River?

Ken Rothman:

You must be talking about sailing, right? Well, I grew up on the ocean and yet never went in a boat. A place called Long Beach, New York. I didn't do any boating growing up there. But when I was an adult and lived in Boston, I knew about community boating, and I thought, "You know, I'd love to learn how to sail." It looked like it would be something interesting. So I read books. Went down to... They had a program with classes. And passed the test, and I took a more advanced course later [inaudible 00:23:16] fair amount about sailing. Love to be out on the water in a sailboat. It is a lot of fun. I learned early on that no matter what's bugging you, what's weighing you down, when you're out in a small sailboat you've got to focus on what you're doing. Takes your mind off everything else.

Lisa Bodnar:

Yeah. Is it hard? I imagine it's really hard to do.

Ken Rothman:

It's easy to screw up. I've been pretty careful about it, so I haven't had any major disasters.

Ken Rothman:

I remember one time I took a friend sailing, I made a pretty rookie mistake. Typical sailing boat community boating has a rounded hull. And the hull shape has a lot of implications, but one of them is, if it's a rounded hull then the boat heels easily. Heel means the boat lists to one side, usually from the wind. This was a boat that was tied up at the dock. The centerboard, which is made out of heavy metal and hangs down [inaudible 00:24:16] some kind of counterweight to it was in the up position. And I was holding a big, heavy, sail that I was going to have to attach to the boat. My friend was there, and I wasn't paying much attention, so I step onto the boat in a way that I've been very careful since then never to do again, which is on the side of the boat instead of along the middle. And so it starts to heel over right at the dock. And then the second mistake is, well, when it does that, you feel yourself falling backwards, so you reach out and grab the sale. And the boat tipped. And It's always embarrassing to capsize a boat when there are lots of people around on the river watching, but there's nothing more embarrassing than capsizing a boat right at the dock with 100 people watching. People wonder how that could happen. And it turns out it's pretty easy.

Lisa Bodnar:

Okay, can I ask you some silly questions?

Ken Rothman:

No. Well, you can try.

Lisa Bodnar:

All right. What's your favorite type of cheese?

Ken Rothman:

Cheese?

Lisa Bodnar:

Yes.

Ken Rothman:

Swiss or Jarlsberg

Lisa Bodnar:

What's your go-to drink at a bar?

Ken Rothman:

Probably a martini.

Lisa Bodnar:

Am I supposed to ask a follow-up martini question?

Ken Rothman:

Yes.

Lisa Bodnar:

Like shaken, stirred, dirty, not dirty?

Ken Rothman:

They're all good.

Lisa Bodnar:

Is there something that most people know a lot about but you don't know anything about?

Ken Rothman:

Podcasts. TikTok.

Lisa Bodnar:

TikTok. I love that answer. Yes.

Ken Rothman:

One of my granddaughters was illustrating TikTok recently, sent a TikTok video

Lisa Bodnar:

Yeah? And did you get it?

Ken Rothman:

It was great.

Lisa Bodnar:

Okay, this is my last question. What's your... I can't even say it with a straight face. What's your favorite type of pie, aside from a causal pie? Someone asked me to ask you that.

Ken Rothman:

It's just silly.

Lisa Bodnar:

I know, I know. My show is a lot of silly, but Ken Rothman, not so silly.

Ken Rothman:

It's cherry pie.

Lisa Bodnar:

Okay. Thank you.

Ken Rothman:

You know, I think you may remember that I told you that with respect to your podcast, and someday I hope to listen to it, those who tune in to hear one of your guests and don't hear other podcasts, they may be interested in the guest. But anyone who turns in more than once is probably interested in Lisa.

Lisa Bodnar:

That's interesting and flattering. I'm not so sure it's true. I think they like to hear people talk about things they wouldn't talk about normally.

Ken Rothman:

All right. It's your podcast, so I'm not going to challenge you.

Lisa Bodnar:

So the book that you wrote, Epidemiology: An Introduction...

Ken Rothman:

Yes?

Lisa Bodnar:

Do you know what this is affectionately known by-

Ken Rothman:

You mean Baby Rothman.

Lisa Bodnar:

Yes. I'm so glad you know that.

Ken Rothman:

Everybody knows that.

Lisa Bodnar:

When you first heard this, people called this Baby Rothman, were you just laughing?

Ken Rothman:

Yeah, I thought it was funny.

Lisa Bodnar:

When I do a Google on Baby Rothman epidemiology, your book comes up first, and all the other entries are of baby registries of babies named Rothman.

Ken Rothman:

That's funny. I didn't know that.

Lisa Bodnar:

I'm excited that you know that people call it that, because I say that all the time to people. "I can't find... It's in Modern Epi. It's too confusing." And I say, "Go to Baby Rothman. It'll be easier in there."

Ken Rothman:

Well, I haven't used the term, but I certainly don't object to it.

Lisa Bodnar:

I'm so happy.

Ken Rothman:

If you Google actually my name... Or at least it used to be true that if you Google my name I didn't come up first. There was a former politician who would come up, Kenneth J. Rothman, same middle initial. And in fact, as we speak, there is a website, selling Baby Rothman in Europe that has a photo of the author and it's this other guy's photo.

Lisa Bodnar:

No. You are kidding me.

Ken Rothman:

I'll send that to you.

Lisa Bodnar:

Please.

Ken Rothman:

It's great to talk to you.

Lisa Bodnar:

It's great to talk to you. I'm really glad you agreed to do this, even though you didn't really want to.

Ken Rothman:

You're welcome. Have to catch up in person sometime.

Lisa Bodnar:

I would love it.

Ken Rothman:

I didn't drink all my wine. Still half a glass.

Lisa Bodnar:

I know. I don't know why.

Ken Rothman:

Did you finish yours?

Lisa Bodnar:

Mine's gone. Yeah, mine's gone.

Ken Rothman:

I was trying to focus. Can't do two things at once.