Academic vs. Applied... Everything

When I posted on Academic vs. Applied Epi I included the following chart:

Then I realized that this breakdown likely works pretty well for other fields too. I sent a link to an economist friend, who responded: "No doubt this is similar with econ. The theoreticians live in a world of (wrong) assumptions, while the practitioners are facing the tough policy challenges. And there are quite a few similarities with the below...such as urgency etc."

You can replace "physicians" with "economists" or many other professions and the chart holds up. Contrasting academic economics researchers with policymakers, the fields for Timeline, Data quality, Scientific values, Outputs, and Competencies needed all hold up pretty well.

Many positions that are basically epidemiological in nature are filled by physicians with clinical training but very little formal public health and epidemiology training, which is strongly paralleled in the policy realm. Some sort of graduate training is generally necessary for many jobs, so those aiming for the applied track tend to get multipurpose 'public policy' degrees often viewed as weak by the more purist academics, while those studying public policy deride the inapplicability of the theoretical work done by academics. And the orientation of many academic fields towards a set of skills primarily useful in pursuits that aren't highly valued by the more applied practitioners may go a long way in explaining animosity between the two camps.

Academic vs. Applied Epi

Third term courses (January through mid March) started back up on Monday. It's amazing how quickly my schedule filled back up with classes, readings, seminars, meetings with students about internship opportunities, TA work, and Student Assembly work. But today I have good news and bad news. The good news: no class because it's a snow day after Baltimore got 5-6" of snow last night. The bad news: my power got knocked out (by the snow or the lightning, hard to tell which) so now I'm stuck staying with friends until I get heat, electricity, and wireless back. Oh well. I have some more substantive posts in the works including two book reviews (The Panic Virus and The Emperor of All Maladies) but here's something short for now.

In my first two terms at Hopkins I took Epidemiologic Methods I and II, the first two of a four-part series on methodology for epidemiology investigators. The methods taught were mostly related to large-scale, long-term studies on the etiology of noninfectious diseases. It's important and challenging stuff because the reality of so many diseases is very complicated, but the emphasis is also quite different from what I envision myself focusing on after grad school.

This term I'm in a brand new class called Professional Epidemiology Methods, the first of a two-part series that emphasizes how epidemiology is generally used in public health practice. To get an idea of the differences between these approaches, Dr. Carlos Castillo-Salgado of PAHO (who, with an MD, JD, MPH, and DrPH, gets the coveted unofficial award for "most degrees of faculty at JHSPH," which is quite an accomplishment given the degree proliferation in public health!) used the following table (click for larger version):

It seems that most graduate training epidemiology related more strongly to the right column -- academic epidemiology. That's vital research of course, but I'm glad to get some additional training oriented at the more applied aspects of epidemiology that I imagine I'll use more often while working on projects.

The Changing Face of Epidemiology

Unlike many scientific disciplines, undergraduate training in epidemiology is fairly rare. I've met a lot of public health students over the past few months, but only a few majored as an undergrad in public health or something similar, and I haven't met anyone whose degree was in epidemiology. For the most part, people come to epidemiology from other fields: there are many physicians, and lots of pre-med student who decided they didn't want to be doctors (like me) or still want to be. This has many implications for the field, including a bias towards looking at problems primarily through a biomedical lens, rather than through sociological, political, economic, or anthropological ones. Another interesting consequence of this lack of (or only cursory) study of epidemiology before graduate school is that the introductory courses in epidemiology at most schools of public health are truly introductory. If you're a graduate student in biochemistry and molecular biology (my undergraduate field), my guess is that it's assumed you know something about the structure of nucleic acids, have drawn the Krebs cycle at some point, and may even have heard the PCR song.

In epidemiology we're essentially starting from scratch, so there's a need to move rapidly from having no common, shared knowledge, through learning basic vocabulary (odds ratios, relative risk differences, etc.), all the way to analyzing extremely complex research. This presents pedagogical difficulties, of course, and it also makes it easier to miss out on the "big picture" of the field of epidemiology.

For one of our earliest discussion labs in my epidemiologic methods course, we discussed a couple papers on smoking and lung cancer. While "everyone knows" today that smoking causes lung cancer, it's a useful exercise to go back and look at the papers that actually established that as a scientific fact. In terms of teaching, it's a great case-study for thinking about causality like an epidemiologist. After all,  most people who smoke never get lung cancer, and some people get lung cancer without ever smoking, so establishing causality requires a bit more thought. Two of the papers we read are great for illustrating some changes that have occurred as epidemiology has changed and matured over the last 50 years.

The first paper we looked at is "The Mortality of Doctors in Relation to Their Smoking Habits: A Preliminary Report," written by Richard Doll and Bradford Hill in the British Medical Journal in 1954. (Free PDF here)  Doll and Hill followed up their groundbreaking study with "Mortality in relation to smoking: 50 years' observations on male British doctors" in 2004 (available here).

A few observations: First, the 1954 paper is much shorter: around 4 1/2 pages of text compared to 8 1/2 in the 2004 article. The 1954 paper is much more readable as well: it's conversational and uses much less specialized vocabulary (possibly because some of that vocabulary simply didn't exist in 1954). The graphs are also crude and ugly compared to the computer-generated ones in 2004.

The 2004 paper also ends with this note: "Ethical approval: No relevant ethics committees existed in 1951, when the study began."

Beyond the differences in style, length, and external approval by an ethics committee, the changes in authorship are notable. The original paper was authored by merely two people: a physician and a statistician. The 2004 paper adds two additional authors for a total of 4 (still small compared to many papers) -- and notably, the two new authors are both female. During those 50 years there was of course great progress in terms of women's representation in scientific research.  While that record is still spotty in some areas, schools of public health today are producing many more female scholars than males -- for example, current public health students at Hopkins are 71% female.

There has been a definite shift from the small-scale collaboration resulting in a paper with an individual, conversational style to the large-scale collaboration resulting in an extremely institutional output. One excellent example of this is a paper I read for an assignment today: "Serum B Vitamin Levels and Risk of Lung Cancer" by Johansson et al. in JAMA, 2010 (available here).

The Johansson et al. paper has ~8 pages of text, 47 references, 2 tables and 2 figures (all of which are quite complicated) and a number of online supplements. Its 46 authors have between them (by my count) 33 PhDs, 27 MDs, 3 MPHs, and 6 other graduate degrees! It's hard to tell gender just by name, but by my count at least half of the authors are likely female.

Clearly, epidemiology has changed a lot in the last 50 years. Gone are the days of (at least explicit) male domination. Many of the problems with the field today are related to information management and large-scale collaborations. Gone are the days of one or two researchers publishing ground-breaking studies on their own -- many of the "easy" discoveries have been made. Yet many of the examples we learn from -- and role models young public health researchers may want to emulate -- are from an earlier era.


As should be obvious now, I got a bit behind on blogging while in Guatemala. I was hopeful that this blog would serve as a reminder to myself to write more regularly, as well as a convenient conduit for sharing travel stories and photos with friends and families. But as I fell more and more behind, I started emailing those stories and photos directly to the friends I felt the greatest need to share them with, and the blog fell behind. I hope to post some photos and additional travel stories from Guatemala in the coming weeks, but mostly I'll try not to make promises I can't keep. So sometimes I'll write about public health and epidemiology, sometimes about politics, about rockets, etc.

I moved to Baltimore about 3 1/2 weeks ago, and a little over a week ago I started classes for a Master in Health Science (MHS) in Global Disease Epidemiology and Control (GDEC) through the Department of International Health at the Johns Hopkins Bloomberg School of Public Health. That's the longest name for a program ever, so we mostly just call it an "MHS in GDEC." Basically, it's an intensive program in international health, especially the epidemiology of infectious diseases and vaccine development and testing. I'll take classes in Baltimore for 4 terms (one academic year), take comprehensive exams in June of 2011, and then head somewhere overseas for 4-12 months for my practicum. I can come back and take additional classes if I want to, but that's optional. GDEC--the program, the people, the pace--is already awesome, and I expect that it will only get more awesome and intense as it goes.