The prep course industry, while it may raise the scores of its clients, actually does not improve their standing or their lifetime incomes as an aggregate. What it does is decrease the variation in LSAT scores, thereby increasing the marginal value of one point. In its application to this paper, all results are pertinent to post prep course scores. However, because not all test-takers take a prep course, those who do have a greater relative advantage than those who do not. On an individual basis, prep courses skew the market for certification of ability, removing some validity in the test's value. If these courses did not exist, each point on the LSAT would be worth less, but the statistical significance of the LSAT in the earnings equation would be higher.

V. Conclusion

I have attempted to assign a quantifiable measure to one point on the LSAT for the law school applicant and for the law school graduate. The results show that the LSAT is in some effect a measure of true ability, but it is far from being a perfect measure. The LSAT is far more important to an applicant than it is to a graduate, and a student should worry about his LSAT score mostly to the extent that it allows him entrance to a "good" school. Once enrolled, the LSAT, which is in some form a measure of ability, still helps to determine performance and future income, but schooling adds a great amount of influence also. In addition, Prep Courses are useful to the individual because they often do raise an individual's score, facilitating her entrance to a better school. In sum, LSAT scores are important, on average, in determining lifetime income. But their effects stay largely on the law school application. Once used to gain admission, their influence in future success, while present, is limited