Problem-based learning, resources, and science in medical education


Robert H. Glew has presented a thoughtful and provocative analysis of some of the current problems facing medical education, focusing his comments on the use of problem-based learning (PBL)11 as a didactic method to teach the basic sciences [1]. Glew has touched on many of the key weaknesses of the program as they have played out at his institution. In particular, he notes that 70% of the basic science lectures are now given by “clinical educators” who are often not up-to-date on the latest basic science information and who are generally pressed by their clinical burden so as to compromise full participation in the teaching process. Glew also notes at his school that Ph.D.s are not committed to PBL. While this is not the case at my institution, there are nonetheless problems integrating Ph.D.s in medical education. Ph.D.s teach “their own,” i.e. Ph.D. students, extensively using PBL usually in the form of journal clubs, teaching at the bench, lab meetings, seminars, national conferences, etc. The world of the Ph.D. scientist is nothing but problem-based, lifelong learning (or one would not remain funded). Therefore, Ph.D.s believe deeply in PBL and life long learning. However, at my school it is true that the basic science Ph.D.s are not well integrated into the culture of the medical school, medical students, or clinical faculty. The Ph.D. faculty is hired without a word uttered to them about expectations for training of medical students. The Ph.D.s come exquisitely trained in the molecular, cellular, and developmental biology of yeast, flies, worms, and frogs and are themselves relatively clueless about gross anatomy, systems physiology, or pharmacology. The learning of these subjects to teach medical students is perceived as a huge burden, detracting from the research mission for which they were hired. This faculty thinks in genomics and proteomics, not in ketoacidosis and portal hypertension. This chasm has been with us for many years, and with the explosion of modern biology, it is only becoming wider.

While Glew provides several reasons why he diagnoses a failure of PBL to deliver the product hoped for by all of us over the past 15 years, his evidence is anecdotal and not quantitative. I can do no better, so I will provide another anecdote illustrating why neither of us can make a scientific statement. For me, the most fundamental flaw in medical education, regardless of pedagogical method, is that we do not know how to measure outcomes. Using standardized tests and shelf exams, we are certainly able to measure the number of facts that a medical student can memorize, but we all agree that this is only the barest minimum of achievement for a young physician. And since we cannot measure those qualities we really want to see in a doctor, are we really ready to say that any one pedagogy has failed? Clearly the challenge before us is not to again reform basic science teaching (which seems to be going on all the time anyway) but rather to come up with a serious assessment paradigm that we can all agree upon.

There are many other responses that could be made to Glew's provocative article in terms of detail, but I would like to use my space to address broader issues. Let's face the facts. The core problem with medical education is resources. This is certainly realized by Glew, but there is more to be said. Medicine, like the rest of the world, is being bought by big money; corporations now “manage” our health. Income disparity continues its logarithmic separation of rich and poor, the latter condemned already in many parts of our global village to die in unspeakable misery with little hope of any medical intervention whatsoever. What does it mean to our training of future physicians that corporations are allowed to make a profit on human suffering? That physicians are becoming drones in the process of healthcare, their worth measured and evaluated by “throughput,” their judgment biased by “capitation,” and their therapeutic prescriptions countermanded by freshly graduated M.B.A.s gelded by the “bottom line”? And in the midst of this, they are expected to keep abreast of an exponentially expanding data base, provide professional leadership in our culture, see five patients an hour, have a family, and teach all this to medical students. The absurdity of this whole scenario borders on terrifying.

If we are going to have a debate about medical education, which I enthusiastically endorse, then let's have the debate in the context of the 21st century with other disciplines besides molecular science on the table. Glew laments,

I was both surprised and disappointed by how shallow their (3rd- and 4th-year medical students) knowledge was of the basic biology that underlies the illnesses of their patients. Even more disconcerting … was their general lack of interest in matters pertaining to pathophysiology and their poorly developed ability to reason their way through a problem from basic principles…. Students seemed to know about as much about human biology as a high school student who had just completed an Advanced Placement biology class.”

I wonder to which basic science Glew refers. I would hazard that this would be a molecular mechanism, not an understanding of why children from a poor neighborhood suffer from abnormally high rates of asthma. Does reasoning using basic principles include noticing that the city has sited the diesel bus terminal in the middle of the poorest, black neighborhood? Or does it include fundamental cause-and-effect relationships between social economic status, nutrition, obesity, and diabetes? I do not advocate lessening the interaction of medicine with molecules, I only advocate for the inclusion of all our sciences. This raises the ugly question of why it is that some sciences are “better” than others. Are the sciences that garner the most money for the profession the ones that are “better?” Whose money is it, and how fair is the process by which it is distributed? Is the money that comes for medical research proportional to the level of human suffering and disease?

If we were really to train medical students for the future, we would have to face some harsh realities: 20–30 years from now we may not be curing our genetically challenged brothers using viral gene therapy, although this will probably be scientifically possible and undoubtedly available to the challenged offspring of the wealthy elite. Nor may most future physicians spend their time alleviating human suffering due to disease using an armamentarium of exquisite designer drugs that will specifically modulate our biochemical, immunological, or developmental pathways gone awry, although this too will most likely be available to those with cash who suffer. Rather our best scientists from around the world tell us that our students will be trying to cope with world health catastrophes brought on by the collapse of one or many of our ecosystem services [2]:

  • Malnutrition due to the loss of topsoil or the overuse of dwindling fresh water supplies (one-third of the world population already does not have access to clean water);

  • Explosions of old or emergent infectious diseases decimating large portions of the population;

  • Responding to trauma from natural climactic disasters due to global warming;

  • Loss of ecosystem services such as the recycling of waste and purification of water due to mass extinctions and species loss;

  • Collapse of the ocean's multiple food and atmospheric services due to the total loss of coral reefs;

  • Abrupt alterations in ocean thermohaline circulation with untold health consequences.

Glew laments the lack of science given to our medical students. I totally concur but ask, what science? Are medical students only responsible for the interactions between our molecules? Is molecular medicine the only lens that the keepers of the future of our health need to know how to focus? In a world of ecosystem collapse, who is going to worry about the downstream targets of phosphatidylinositol 3-kinase? What will we be doing with the richness of the human genome?

Perhaps the first step to a solution is not for us to debate about whether to use PBL, lectures, or other teaching pedagogies. Perhaps the first step to improving medical education would be for physicians to unionize (perish the thought!) to become politically active, to wrest back control of health care through collective bargaining, and to compel the corporate elite to pay for the teaching of new physicians not to mention subsidize health care for the poor. Only then can we realistically worry about the use of PBL to impart not only the mechanisms of ketoacidosis in diabetes but also the recognition of the links between the siting of diesel bus depots and asthma in poor communities and the absolute importance to world health and to a humanitarian ethic of equitable distribution of antiviral drugs in sub-Saharan Africa, aggressive treatment of multidrug-resistant tuberculosis in Peru, and basic health care in Haiti. All of this, of course, should be centered on the absolute best of our world's science. Then, perhaps, we will be preparing our students for what is really coming at them during their professional careers, and we will have some resources to pay for it.


  1. 1

    The abbreviation used is: PBL, problem-based learning.