The Perils of ‘Best Practices’: John Cutler on Evolving Medical Wisdom

In a recent LinkedIn post, John Cutler revisits the historical practice of bloodletting to draw parallels with modern business and technological approaches. Cutler uses the evolution of medical understanding to illustrate how deeply ingrained ‘best practices’ can persist long after they have ceased to be effective, or even become harmful.

The Persistence of ‘Best Practices’

Cutler begins by framing bloodletting as a widely accepted ‘best practice’ in medieval medicine. He highlights how, over centuries, the practice persisted not necessarily due to its efficacy, but because a new, superior understanding of disease had not yet emerged to replace it. This inertia allowed practitioners to rationalize its continued use, even when evidence to the contrary began to surface.

“When the patient rises and thanks God, I will not quarrel with the means. If the bleeding eases him, who am I to doubt it?”

This quote, attributed to Brother Anselm of Slightbetterment (c. 1280), exemplifies the mindset Cutler describes: a reluctance to question a practice that, in some anecdotal instances, seemed to yield positive results, regardless of underlying efficacy. Cutler points out that as late as 1588, Dr. Bludworth defended bloodletting by suggesting the issue was not the practice itself, but its application: “Bloodletting has not failed us. Rather, we have failed to apply it with sufficient rigor, frequency, and respect for context.” This defense, Cutler implies, is a common tactic to preserve a failing methodology.

Shifting Paradigms Through Observation and Data

The turning point, according to Cutler’s analysis, came not from outright rejection but from the gradual outperformance of bloodletting by alternative approaches. He notes that in the 17th and 18th centuries, practitioners in more demanding environments, such as army and naval surgeons, began to rely more on observation, rest, nutrition, and hygiene. These practical, outcome-oriented methods led to improved results, even as the established doctrine remained.

“At sea, one learns quickly that theories do not heal wounds. Cleanliness, nourishment, and patience do. Bleeding has its place, but it is smaller than the books would suggest.”

Cutler further explains how the work of figures like Pierre-Charles-Alexandre Louis in the early 19th century made bloodletting ‘awkward’ by introducing quantitative outcome analysis. While the data existed, it lacked the ‘standing’ to immediately overturn the established practice. The true shift, however, occurred with paradigm-changing discoveries in the mid-to-late 19th century.

The Impact of Foundational Science

The advent of germ theory and cellular pathology, championed by scientists like Pasteur and Virchow, fundamentally altered the understanding of disease. As Cutler articulates, once disease was understood in terms of specific causes, cells, and microbes, bloodletting ceased to be a logical or sensible intervention.

“The patient before me is not an average. Tables may satisfy clerks, but the physician must treat the individual constitution.”

This quote, from Dr. Augustus Casebycase (c. 1834), reflects a tension that Cutler highlights: the conflict between generalized practices and individual patient needs, a tension that deeper scientific understanding eventually resolved in favor of evidence-based, targeted treatments. Cutler concludes by noting that bloodletting wasn’t so much disproven as it was superseded by a more accurate and effective framework of understanding, eventually becoming irrelevant to explain.

Lessons for Today’s Business Landscape

Cutler’s historical account serves as a cautionary tale for contemporary fields, particularly in technology and business. He implies that many current ‘best practices’ in areas like AI implementation, agile methodologies, or specific marketing tactics may face a similar fate. The key takeaway, as Cutler suggests, is the importance of continuous questioning, empirical validation, and being open to entirely new paradigms rather than merely refining existing, potentially flawed, approaches.

Ultimately, Cutler’s post underscores that true progress comes not from defending outdated methods, but from embracing new knowledge that offers a more accurate and effective way to achieve desired outcomes. The legacy of bloodletting, he argues, is a powerful reminder to critically evaluate our own ‘best practices’ and remain vigilant for the next paradigm shift.