Statistics and commentary on the state of criminal justice:The best data, federal and state, are on this site:
State conviction rates in jury trials are only 35-66%, depending on the crime.
Federal conviction rates a trial are probably less than 90%. Both the prosecutor and defense attorney have reasons to inflate the risk. A law review article gave this data:
"The conviction rate in federal court at trial is about 80%. See U.S. Department of Justice, Bureau of Justice Statistics 1998 Sourcebook of Criminal Justice Statistics 410-11 (Kathleen Maguire & Ann L. Pastore eds., 1999) (3,629 convictions and 1,081 acquittals); U.S. Department of Justice, Bureau of Justice Statistics 1997 Sourcebook of Criminal Justice Statistics 400-01 (Kathleen Maguire & Ann L. Pastore eds., 1998) (3,730 convictions and 893 acquittals); U.S. Department of Justice, Bureau of Justice Statistics 1996 Sourcebook of Criminal Justice Statistics 450-51 (Kathleen Maguire & Ann L. Pastore eds., 1997) (4,074 convictions and 902 acquittals). Kalven and Zeisel found a lower rate of conviction, but still one that was much greater than the rate of acquittal: 64.2% versus 30.3%. Kalven & Zeisel, supra note 7, at 56. While conviction rates and factual guilt may not be precise correlates, there is (hopefully) some correlation, which does suggest that far more guilty defendants than innocent defendants are tried. Of course, we cannot be sure that this is true."
This website identifies the evils of plea bargains: www.lawmall.com/pleabarg
It cites an article declaring that "Criminal Defense Lawyers Are Leaving the Field - Claim They Are Unable to Represent Their Clients Properly Under This New [Star Chamber] System - 3/4/02 New York Magazine Article"
From 1997 to 2003, the average number of trials per federal district court judge in Arizona fell from 37 to only 16. That includes civil and criminal cases. Now, there's no reason to expect a decline in civil trials, so the implication is that criminal trials have almost disappeared. And that's not because defendants want to plead guilty. It can only be because federal prosecutors are terrorizing them with sentencing threats.
The 14 pages at this link contain informative DOJ statistics: www.ussc.gov/JUDPACK/2001/wa01.pdf