Most law schools use an index to rank applicants.
The index is calculated based on a numerical value assigned to the LSAT, GPA, and sometimes the undergraduate school attended. Each school determines its own formula for weighing these factors. The presumptive admits will generally be accepted barring any negative information in the file. Likewise, the presumptive denies will generally be rejected unless there is some compelling information in the file. The majority of applicants in the pool will fall somewhere in the middle.