Scoring of the LSAT is based on the number of questions answered correctly on the three scored multiple choice sections of the exam -- this is referred to as the "raw score." All test questions are weighted equally, and there is no penalty for guessing or incorrect answers. The "raw score" is then converted to a scaled LSAT score ranging from 120 (lowest possible score) to 180 (highest possible score).
LSAT scores reflect an estimate of an examinee’s actual proficiency in the skills tested on the exam. An examinee’s actual proficiency may vary slightly from exam attempt to exam attempt, and may not be perfectly reflected by the officially administered exam score.
Therefore, LSAT scores are reported to law schools along with a score band to provide an estimated range of scores, including scores slightly higher and slightly lower than the score received to capture where the examinee’s actual proficiency likely falls. For example, an examinee who receives an officially reported score of 167 would be reported along with a score band of 164 to 170.
Additional information about LSAT score bands and how they are calculated can be found on LSAC’s website.