A Cynical View of Law Firm Hiring Practice
This is, admittedly, a non-scientific, non-academic approach, but I want to pull together the various stories, impressions, and tall tales of the law firm hiring process, and see if I can make a few tentative predictions. I've been inspired by lectures from career services, my upcoming exams, and a brief glance at my current debt level, so this might be a little less optimistic than normal.
1900-1950: Although legal education remained the norm, some firms would still hire and train under an apprenticeship system. Indeed, Supreme Court Justice Robert Jackson (for whom the current Chief Justice clerked) was trained in that fashion. A student's performance in law school, however, remains determinative of his career prospects.
1995: For some time, rebellious theorists have questioned whether a third year of law school is necessary. 1L grades are determinative of students career prospects. Some students spend their summer after 1L year pursuing non-law interests. Whatever the theorists think, 3L year is still mandatory as either a restraint of trade or ritual formality.
2003: At least one admitted untrained theorist  wonders if the second year of law school is unnecessary. First semester 1L grades are determinative of job prospects for post-1L summers. 1L grades and 1L summer placements sort out 2L summer placements, and law firms choose from among 2L summer placements. 3L year remains necessary.
Which leads to my predictions:
2010: Enterprising law firms realize that a pedagogical system which does the vast majority of its ranking function in the first 16.5% of a three year course is probably testing extraneous factors--who's learned how the test system works in the first semester, instead of correcting exam-strategies after a dry run, for instance. Firms therefore begin asking for LSAT results and application essays. LSAC IPOs to great fanfare; BarBri exam courses end. 3L year remains as a restraint of trade or ritual formality.
The further future is indeterminate, but I predict one of two possible courses:
2040: Genetic testing has advanced, allowing law firms to test newborn babies for legal aptitude. After SATs, LSATs, IQ tests, or 1L exams, firms finally have a competitive measure in which 'test prep' is not a factor in success. (BarBri, however, begins offering hopeful parents Guides to Successful Legal Conception: What Are the Firm Test 'Positions'?) 1L year now a relaxed post-college sabattical. 3L year remains as a ritual formality.
2040: Rising numbers of applicants, broader grade curves, and more compressed time schedules lead law firms to conclude that using 3rd grade aptitude tests have the same problems as SATs, LSATs, or 1L exams when Kaplan enters the test prep market in a marketing alliance with Barney. Realizing that they're doing most of the black-letter law education themselves, law firms complete their circle by hiring legal apprentices based upon a holistic interview process. Very faint peals of laughter are heard over the grave of Justice Robert Jackson...
 Yours truly.