It seems as if the media reports some significant advance in health care every day. These announcements lead both patients and clinicians to assume that the level of health care provided by contemporary practitioners is near flawless. Unfortunately, this is not the case. For example, the pathology literature has consistently revealed that approximately 8-12% of autopsied patients die a premature death due to misdiagnosis, while another 20% suffer from one or more major illnesses that are undiagnosed during the patient's lifetime. Furthermore, in patients wherein a correct diagnosis is made, research suggests that up to 100,000 patients die unnecessarily each year from treatment-related errors. While the evidence attributes many of these treatment-related errors to the complexities inherent to health care 'systems', misdiagnoses are largely the result of judgement errors made by individual practitioners.
Why can't medical training institutions provide medical students an educational experience that assures their ability to provide the highest possible levels of DDX care? The answer to this question begins with the following.
While there has been a gradual realization that medical practitioners must improve their diagnostic (DDX) capabilities, there is little evidence that medical educators and training institutions have made any significant changes or improvements in either instruction towards, or assessment of, DDX competence. For example, many medical training programs continue to utilize traditional, classroom-based DDX instructional approaches that have lead to, and perpetuate, diagnostic errors. Furthermore, the DDX assessment procedures widely utilized in medical training programs are actually not designed to provide any documentation that students have attained any objective DDX competency criteria in even the most common and/or important patient care problems and disease etiologies.
It is important to note however that even with improved educational approaches, the development of DDX competence would still most likely represent the most complex learning task confronting medical students. To begin, the development of DDX competence requires much more than simply memorization — much more than simply acquiring a 'declarative knowledge base' representing the most common and important disease differentials likely to cause a given patient problem, and, the signs and symptoms that characterize any given disease on that list of disease differentials. Memorization of declarative knowledge is only a first step towards the development of DDX competence.
Recent research has made clear that for students to achieve competence in a given endeavor, they must be given extensive practice opportunities. In order to develop diagnostic competence, these practice opportunities must be first deliberately designed to allow students to focus on a given patient care problem such as chest pain, difficulty breathing, abnormal vaginal bleeding, etc. Thus, problem focused, deliberate practice appears to enable students to develop 'procedural knowledge' — knowledge of how to apply their declarative knowledge so that they might gradually increase their diagnostic capabilities.
The development and refinement of both declarative and procedural knowledge in turn requires yet a second critical learning factor — 'immediate feedback'. Immediate feedback tailored to the numerous, and, specific diagnostic errors students make is essential to gradually achieve some minimal level of DDX competence. A third critical learning factor is practice with cases representing increasingly less typical case presentations of common and important disease they will soon be confronted with during clinical rotations. Until medical training institutions and faculty provide the kinds of training experiences that support the development of procedural knowledge (i.e., problem focused DDX training, deliberate practice, individually tailored feedback, and, increasingly more difficult case challenges), medical students will continue to find that the development of DDX competence is the most difficult and complex learning task confronting them in medical school.
ACDET was founded upon the belief that advances in our understanding of these cognitive factors underlying the development of DDX competence are now sufficient to create approaches and technologies that will dramatically improve the DDX capabilities of medical students. The following material describes in more detail, some of the recent literature and evidence that ACDET has used in creating our KBIT DDX tutorials — DDX instructional and assessment tutorials that efficiently and effectively improve the DDX capabilities of medical students.