Although plea bargaining is often criticized, more than 90 percent of criminal convictions come from negotiated pleas. Thus, less than ten percent of criminal cases go to trial. For judges, the key incentive for accepting a plea bargain is to alleviate the need to schedule and hold a trial on an already overcrowded docket. Judges are also aware of prison overcrowding and may be receptive to the "processing out" of offenders who are not likely to do much jail time anyway.

For prosecutors, a lightened caseload is equally attractive. But more importantly, plea bargaining assures a conviction, even if it is for a lesser charge or crime. No matter how strong the evidence may be, no case is a foregone conclusion. Prosecutors often wage long and expensive trials but lose, as happened in the infamous O. J. Simpson murder trial. Moreover, prosecutors may use plea bargaining to further their case against a co-defendant. They may accept a plea bargain arrangement from one defendant in return for damaging testimony against another. This way, they are assured of at least one conviction (albeit on a lesser charge) plus enhanced chances of winning a conviction against the second defendant. For the defendants, plea bargaining provides the opportunity for a lighter sentence on a less severe charge. If represented by private counsel, defendants save the cost for trial and have fewer or less serious offenses listed on their criminal records.