Like it or not, the LSAT is the single most important factor in determining your admission to law school. The LSAT was designed to predict your success in the first year of law school. Unfortunately, law schools have relied more and more heavily on LSAT scores because the average LSAT score of their students impacts the law school's ranking. The LSAT measures: Verbal Facility; Analytical Skills; Logical Reasoning; Stability Under Pressure; Tolerance of Ambiguity; Ability to Deal with the Unfamiliar.
The LSAT is offered 4 times a year and contains five multiple-choice sections along with a writing sample. Each section is separately timed with between 120 and 130 questions each. It takes 3 1/2 hours (not including breaks) to take the test, with total time on test day being about 5 hours. The question types include Reading Comprehension, Analytical Reasoning (often called Logic Games) and Logical Thinking. There is no fixed sequence in which sections of the different question types are presented; the order in which they appear in test booklets varies from one edition to another. Only four of the five multiple-choice sections are scored. They consist of one section of Reading Comprehension, one section of Analytical Reasoning, and two sections of Logical Reasoning. The one unscored section could be of any one of the three question types, and its placement in the test is random.
The LSAT score is a three-digit number ranging from 120-180 and is determined by the total number of correct answers to the approximately 99-101 questions contained in the four scored sections. There is no penalty for guessing. The LSAT score is accompanied by a percentile ranking that is based on the distribution of scores among all test takers on all administrations of the test over the most recent three full testing years. The writing sample is not scored.
The skills which the LSAT tests are ultimately the product of years of both formal and informal education. Preparation involves familiarization with the format of the test and repeated use of authentic practice tests under simulated test conditions. In other words, practice, practice, practice. Every disclosed test since 1991 is available for purchase from LSAC, either as an individual PrepTest or as part of a book containing multiple tests. One test is provided free of charge in the LSAT/LSDAS Information Book, which is available in the Office of Career Services, or downloadable from LSAC's web site. The Office of Career Services typically offers a practice LSAT in the fall and in the spring. An excellent web site to use when preparing for the LSAT is LSAT Exam Practice Test.
You may wish to take a LSAT prep course. Pre-law advisors disagree over the usefulness of prep courses. They are expensive, and generally their services do not offer anything that prospective test takers cannot, given time and motivation, do on their own. Take a practice test first to see how you do. If you scored well, and your practice score and GPA place you solidly within the admissions criteria of the law schools you wish to attend, you probably do not need to take a prep course. If you are self-motivated, you may not wish to spend the money on a prep course.
You should never take the LSAT with the mindset that you can always take it again. While it is true you can take it again, your scores will be averaged. If you prepared well for the test and were feeling good on test day, chances are your scores from a second administration won't be much different, and there's always the danger that you could score worse. If you absolutely bombed the test, there are provisions for canceling your score, but you must make that decision very quickly after taking it. LSAT test takers receive their LSAT score reports by email three weeks after the test date.