People are often surprised to learn certain things about the Law School Admissions Test, in particular that a substantial portion of its content appears irrelevant to “being a lawyer.” A typical LSAT “game” reads something like, “If Frank lets go of his balloon first and Anna lets go of her balloon last, how many different combinations of kids could lose balloons in between?” Imagine sudoku but with words. This, and yet law schools give applicants’ LSAT scores tremendous weight in making their admissions decisions.

But they haven’t always. The test itself is only 65 years old, and the history of the LSATprovides some insight into why, exactly, it can seem to have so little to do with the field of law.

Prior to the LSAT, there wasn’t one admissions test that all law schools used–there were a couple of well-known ones, but their use wasn’t universal. In 1945 the admissions director at Columbia Law School, unsatisfied with the tests currently available, wrote to the President of the College Entrance Examination Board that he wanted to discuss the creation of a new one. When they finally met two years later, they envisioned a test intended to correlate with first year grades “on the assumption that first-year performance is highly correlated with later success in law school and in legal practice.” The key was law school performance, not bar exam passage since, they noted at the meeting, “everybody passes [bar exams] sooner or later” (quote pulled from the same article linked to above). With this goal in mind, they invited Harvard and Yale to sign on to the plan, which they did, followed by other schools.

The LSAT was never intended to measure aptitude for the practice of law; it was designed to measure potential success as a law student based on the belief that LSAT performance would correlate with law school performance, and that law school performance would correlate with one’s professional success thereafter.

So how have all these expected correlations played out?

A 2011 report by the Law School Admissions Council (which administers the LSAT) claims that the LSAT is a better predictor of law school performance than undergraduate GPA, and that GPA and LSAT score combined is a better predictor than either one, alone, concluding that “these results, combined with similar results from previous studies, support the validity of the LSAT for use in the law school admission process.” I know: shocking that an LSAC study would affirm LSAC’s continuing usefulness. But there is also, interestingly, some evidence that preparing for the test itself alters your brain–that learning LSAT-relevant reasoning can actually make you smarter. Silvia Bunge, associate professor in the UC Berkeley Department of Psychology and the Helen Wills Neuroscience Institute says:

“A lot of people still believe that you are either smart or you are not, and sure, you can practice for a test, but you are not fundamentally changing your brain … Our research provides a more positive message. How you perform on one of these tests is not necessarily predictive of your future success, it merely reflects your prior history of cognitive engagement, and potentially how prepared you are at this time to enter a graduate program or a law school, as opposed to how prepared you could ever be.”

But the process of studying for the text had visible effects on brain connectivity:

The structural changes were revealed by diffusion tensor imaging (DTI) scans of the brains of 24 college students or recent graduates before and after 100 hours of LSAT training over a three-month period. When compared with brain scans of a matched control group of 23 young adults, the trained students developed increased connectivity between the frontal lobes of the brain, and between frontal and parietal lobes.

If this is true, perhaps what’s ultimately so useful about the LSAT isn’t how well it’s correlated with first-year grades, or how well it predicts overall success, but how preparing for it actually makes people better at reasoning. That may make them better at the LSAT sure, but ultimately it’s because they’ve been made better thinkers, which we can infer without getting too crazy likely means better law students and lawyers. That would make the LSAT, rather than just a weeding out tool or a litmus test, a kind of phase of legal training, itself.

As for whether doing well in law school makes you a better lawyer, well, a 2010 studydoes suggest that it’s a good predictor of your career: “the consistent theme we find throughout this analysis is that performance in law school–as measured by law school grades–is the most important predictor of career success. It is decisively more important than law school ‘eliteness.’” This should dispel some worry that what school you get into matters more than how you do once you get there (a commonly held viewamong law school applicants).

So if the LSAT is a reasonably reliable predictor of law school performance, and if law school performance is a reliable predictor of career success, can we say that the LSAT can predict if you’re going to be a good lawyer? I’ll leave that one for you to reason out, for your own sake.