China's low acquittal rate

In a speech earlier this month, Supreme People's Court president Xiao Yang stated that in the 9-year period from 1997 through 2005, 41,038 criminal defendants had been found innocent, representing 0.66% of the number of persons on whom judgment had been pronounced. [Source] He is not reported to have commented on whether he thought this figure was too high, too low, or just right.

Without information on what kind of cases are brought to trial - information that only in-depth fieldwork would reveal - it's hard to know what to make of this number. It is theoretically possible that doubtful cases are never brought to trial, although recent well publicized cases of miscarriages of justice (for example, here and here) make that hypothesis a bit implausible. But just how implausible is impossible to say.

The acquittal rate in the United States is much higher: in federal courts, a recent study found that the average conviction rate in jury cases was 84%, while judges convicted slightly more than 50% of the time; a quick Google search finds estimates of the overall acquittal rate ranging from 17%
to about 25%. (I have not researched this extensively and would welcome better numbers.)

East Asian countries have much lower acquittal rates. Consider this report on South Korea:

Prosecutors normally indicted only when they accumulated what they considered overwhelming evidence of a suspect's guilt. The courts, historically, were predisposed to accept the allegations of fact in an indictment. This predisposition was reflected in both the low acquittal rate--less than 0.5 percent--in criminal cases and in the frequent verbatim repetition of the indictment as the judgment. The principle of "innocent until proven guilty" applied in practice much more to the pre-indictment investigation than to the actual trial.

The acquittal rate in Japan is less than 1 percent. [Source] (For a good study of the Japanese criminal prosecution system, see David Johnson, The Japanese Way of Justice: Prosecuting Crime in Japan (2002), reviewed here.)

Interestingly, Taiwan's acquittal rate is 12% [source] - lower than the US but still in the same ballpark, while conspicuously higher than that of Japan or South Korea, to whose criminal justice systems its own bears a much higher formal resemblance. Another source reports a somewhat lower rate:

According to statistics released by the Ministry of Justice, the proportion of those released without prosecution is about 20 percent yearly. The conviction rate of those that go to trial is more than 90 percent.

The Dui Hua Foundation has a report here that looks at the issue of Chinese conviction rates in political cases in particular.