In addition, cases only go to trial that are contestible—where the prosecution thinks it can be proved beyond reasonable doubt but the defence does not.
And it’s worth noting that the fraction of cases that go to trial is quite small. The best statistics I could find was the table in EXAMINING THE WORK OF STATE COURTS, 1998 page 72. Out of all criminal cases, the prosecutor or court dismisses 18.4%, the accused pleads guilty in 63.4%, and only the middle 3.7% go to trial. (There is also a mysterious 14.5% “other” category...).
Of course, these percentages do not directly reflect the state of the evidence: because of plea bargaining there is an expected utility calculation involved as well.
And it’s worth noting that the fraction of cases that go to trial is quite small. The best statistics I could find was the table in EXAMINING THE WORK OF STATE COURTS, 1998 page 72. Out of all criminal cases, the prosecutor or court dismisses 18.4%, the accused pleads guilty in 63.4%, and only the middle 3.7% go to trial. (There is also a mysterious 14.5% “other” category...).
Of course, these percentages do not directly reflect the state of the evidence: because of plea bargaining there is an expected utility calculation involved as well.