Opinion writer

Here’s a study that isn’t at all surprising.

Black people convicted of murder or sexual assault are significantly more likely than their white counterparts to be later found innocent of the crimes, according to a review of nearly 2,000 exonerations nationwide over almost three decades.

Innocent blacks also had to wait disproportionately longer for their names to be cleared than innocent whites, the review, released on Tuesday by the National Registry of Exonerations, found. Blacks wrongfully convicted of murder, for example, spent an average of three more years in prison before being released than whites who were cleared.

“It’s no surprise that in this area, as in almost any other that has to do with criminal justice in the United States, race is the big factor,” said Samuel R. Gross, a University of Michigan law professor and a senior editor of the registry, a project of the law school that aims to provide data on false convictions to prevent them in the future.

And as with capital punishment, the race of the victim matters in addition to the race of the accused:

Only about 15 percent of all murders committed by black people involve white victims, yet 31 percent of blacks eventually cleared of murder convictions were initially convicted of killing white people, they found.

Misconduct, such as hiding evidence, tampering with witnesses or perjury, may also have contributed to the racial disparity.

The authors found such wrongdoing was present in 76 percent of cases in which black murder defendants were wrongfully convicted, but just 63 percent of cases in which white defendants were exonerated.

Speaking of exonerations, the Innocence Project turns 25 this year. I can’t think of many groups that have done better work to expose and correct the shortcomings of the criminal-justice system.