By Andrew Reed, J.D. candidate, Harvard Law School
STUDENT VOICES: The views expressed below are those of the student author and do not necessarily reflect the position of the Access to Justice Lab.
For centuries, scurvy plagued maritime voyagers. Sailors perished from the disease, which confounded medical minds for most of human history. Centuries of medical speculation yielded nothing but incorrect and, by today’s standards, ridiculous theories about what causes it. Salted meat, homesickness, copper pans, and (quite ironically) too much fruit were all thought at one point to cause scurvy. By the mid-1700s, the leading theory was “bad air,” a reference to the foul, damp conditions in which sailors lived.
In 1747, a Scottish physician named James Lind designed an experiment to test these hypotheses. Lind gathered “twelve cases of scurvy as similar as I could have them,” and divided them into six groups of two. He controlled their diet for the next several weeks.
The first group received cider; the second, elixir of vitriol (a mixture of sulfuric acid and alcohol); the third, vinegar; the fourth, salt water; and the fifth, a purée of various roots and vegetables. The sixth group got oranges and lemons. Within a week, the diet of citrus had rendered one of the men fit to return to duty. The other diets had little to no effect.
Without even knowing it, Lind had conducted what many regard as the first controlled trial, and what some regard as the first randomized controlled trial, in medical history. The authority on the latter proposition is more mixed. Some, like the FDA’s Center for Clinical Trial Innovation and the Naval Institute, have given Lind that honor, but others say he failed to randomize properly. Either way, Lind’s experiment marked a key moment in medicine’s transformation from a field of exotic elixirs and bad air to the mostly evidence-based discipline we know today.
The legal profession, by contrast, is still stuck in its bad air phase. Where today’s medical field has evidence, the legal field has anecdotes. Where it has science, we have intuition.
It doesn’t have to be that way. There is nothing so unique about the practice of law that makes it immune to data. Why should law, unlike every other discipline, not submit itself to math and science?
Law could use a data-driven renaissance, like the one the medical field experienced in the last few centuries. Thankfully, we can learn from medicine’s example.
A (Very) Brief History of Medical Practice
In Europe, early forms of medicine relied upon ancient texts from figures like Hippocrates and Galen. The measure of a physician was based on his mastery of their theories and ability to perform traditional procedures like bloodletting and trepanation. During this period, medical knowledge passed from one generation of physicians to the next via practice and tradition.
But with time, medicine began to reject the old way of doing business.
It took a while. It wasn’t until the 1500s, more than a millennium after the days of Hippocrates and Galen, that the ancient theories received any real scrutiny. Under that scrutiny, the ancient texts withered.
But tradition-based medicine didn’t just go away. The old traditions were merely replaced with new traditions supported by the same amount of evidence—none.
That situation began to change in the 1800s when a small group of reformer-physicians in the United States and the U.K. endeavored to universalize medical research. They created medical journals like the New England Journal of Medicine (1812) and The Lancet (1823). For the first time, contemporary research would be cultivated and published widely for physicians around the world to follow, to challenge, and, in either case, to benefit from.
Still, for over one hundred years more, statistical methods remained absent from medical research. This was at least in part because the field of statistics itself was essentially non-existent. Once the field was born, it took a while for the branch of inferential statistics to reach full maturity. In the 1900s, statisticians like R. A. Fisher and Jerzy Neyman developed statistical methods that could more easily and effectively judge scientific conclusions. With those tools in hand, fields like genetics, economics, physics—and, yes, medicine—incorporated inferential statistics into their research and, eventually, their practices.
Then, for the first time in 1948, the British Medical Journal published the results of a field randomized controlled trial—a joint study by British and American researchers that verified that streptomycin was effective in addressing tuberculosis.
From there, the trajectory of medicine, in fits and starts, has remained generally upward, aimed toward greater reliance on science and data to make treatments safer and more effective. By 1968, the director of the National Heart Institute would remark that the medical profession had given way to “the benevolent tyranny of statisticians,” and their “twin watch dogs of probability, alpha and beta.” (For the uninitiated, roughly, alpha relates to false positives and beta to false negatives.)
Following Medicine’s Lead
Law is a millennium behind medicine (give or take a few centuries). While medicine has evolved into a science-based discipline with rigorous empirical standards, law still operates on precedent, rhetoric, and theory untethered to scientific evidence. If the legal field is going to undertake a similar transformation, it would do well to follow medicine’s lead. Here are three lessons law can learn from medicine.
Lesson #1: Tradition and personal experiences are not substitutes for hard evidence.
The fundamental lesson of the medical renaissance is that tradition and personal experience are not substitutes for hard evidence. Traditions and anecdotes can mislead, sometimes badly. Overreliance on traditional wisdom led medicine to accept the theories of figures like Hippocrates and Galen who were once considered brilliant, but who ultimately proved to be mistaken. It should not have taken thousands of years to realize that draining someone’s blood or drilling a hole in their head, in addition to being gruesome, was not a promising treatment. And yet, physicians still performed them, because that was what they were taught to do.
Finally faced with proof to the contrary, however, expertise yielded to evidence; proof triumphed over precedent. Medicine transformed itself into an evidence-based field.
The law has yet to do likewise. The legal system still embraces tradition and personal experience in ways that defy empirical reality.
To some extent, appeals to authority are baked into the legal system. Every time a lawyer cites a Supreme Court case, they appeal to authority, regardless of whether that authority is correct. As Justice Robert Jackson, speaking about the Supreme Court, famously quipped, we are “not final because we are infallible, but we are infallible only because we are final.” In our system, citing a Supreme Court opinion, even if the opinion is wrong, is good lawyering.
What is not good lawyering, however, are the scores of other aspects of law that are tethered only to historical practice. Consider, for example, how eyewitness testimony, despite decades of psychological research revealing its unreliability, is still at the forefront of trials.
Consider too how slowly courts have adopted technology that could improve access to justice. While fields like medicine have undergone digital transformation, many courts still operate with paper filings, exclusively in-person appearances, and other inefficient processes that limit accessibility.
While medicine has gradually built a culture of evidence-based practice and incremental improvement, the law remains stubbornly attached to the past.
One solution to modernizing our legal system is to embrace evidence-based approaches like medicine did. This means systematically evaluating the effectiveness of everything we do. Like medicine, law can start small with a few pilot programs to test innovations before widespread adoption. The law must finally accept that neither personal experience nor tradition can supersede hard evidence.
Lesson #2: Habits form early.
Medical education underwent a transformation in the 1990s with the introduction of “evidence-based medicine” (EBM) curriculum. This change came as a response to the volume of research that had accumulated over the previous several decades. The data was there, but physicians needed to know how to use it.
As a result, today medical students learn not only about anatomy and pharmacology, but also how to formulate clinical research questions, search medical literature for relevant data, and apply those findings to patient care.
Physicians are not just taught to follow the crowd, or even blindly follow the evidence; they are taught how to understand and evaluate the evidence in a scientifically rigorous manner.
Legal education, on the other hand, remains largely unchanged since Dean Christopher Columbus Langdell of Harvard Law School introduced the case method in 1870. Where medical schools have embraced empirical science, law schools still teach through appellate opinions and theoretical reasoning.
There is no such thing as “evidence-based law.” There should be.
Just as physicians ask, “What does the data show?” before they treat a patient, lawyers should be trained to ask, “What empirical support exists for this approach?” before taking a position—whether it be in representation of a client or in helping reshape the system itself. The stakes are too high for anything less.
Lesson #3: Data must be usable.
In 1972, physician Archie Cochrane published an article lamenting the lack of a centralized repository for medical research. If a doctor wanted to find studies on a particular topic, they’d have to comb through dozens of journals to find relevant studies. There might be 20 or 30 studies on the same topic, which they would have to read individually to understand their methodology and results. Only then could they fully understand the scientific consensus, if one even existed.
Cochrane’s ideas led a group of British physicians to create the Cochrane Collaboration in 1993. This organization was established to collect, review, and systematically synthesize medical research to make scientific findings easy for physicians to understand and implement in their practices.
To have a data-driven renaissance of its own, the legal profession needs to create a similar infrastructure. A legal version of Cochrane would systematically evaluate research on legal practice—from jury selection and contract writing to depositions and negotiations. Researchers could then conduct meta-analyses on the effectiveness of various interventions to see what works best.
Just as Cochrane transformed medical decision-making, systematic reviews of the (hopefully) forthcoming legal research will help establish among judges, lawmakers, and practitioners a standard of legal care—making the entire system both more fair and more effective.
Evidence-Based Law
Ultimately, the path forward for law is clear, though not without challenges. Just as medicine moved from bloodletting to biotech, the legal profession has the chance to have its own revolution. The legal field awaits its own James Lind—someone to break through conventional wisdom with empirical reality. Like the sailors whose lives were saved by Lind’s simple experiment, countless individuals caught in our legal system stand to benefit from evidence-based approaches that challenge “bad air” theories of jurisprudence.
This transformation won’t happen overnight—medicine’s took centuries—but the potential rewards are substantial: a more efficient, effective, and accessible legal system for all.
It’s time for the law to take its medicine.
If you’re interested in more on this topic, listen to our Proof Over Precedent podcast episode.