In Junk Science and the American Criminal Justice System (Akashic, Apr.), Fabricant, the Innocence Project’s director of strategic litigation, presents the horrifying story of how Americans have been wrongfully convicted, and executed, based on “expert” testimony.

Is the idea that people don’t understand science’s limitations at the root of the many problems you’ve found with things like bite-mark and blood splatter analysis?

In a law-and-order context, there’s no skepticism around forensics whatsoever. One should bring appropriate skepticism to any science, because scientists themselves are skeptical, and they’re never absolute about their findings. And I think that we, as human beings, want certainty. What we know today might not be true tomorrow, but if we’re going to embrace science, then we have to embrace uncertainty.

How does that relate to the issues you’ve encountered in criminal trials?

In forensics, that means you should exclude from a jury’s consideration anything that hasn’t been properly validated and demonstrated to be reliable. And a jury must have an appropriate means by which they can weigh the probative value of forensic testimony that is admitted—how likely it is that this person is going to be right.

How scientifically literate are the lawyers in these cases typically?

Most are scientifically illiterate, and often junk science will get put in front of juries who are all scientifically illiterate themselves. We are advocating for scientific literacy for the defense bar. And I have a huge project that I’ve been working on for the last year and a half, an effort to teach the defense bar about peer review, testability, and error rates. Those are fundamental concepts of science. That’s what the Supreme Court has said that judges need to be considering before they introduce so-called scientific expert testimony, and the percentage of lawyers who actually know anything about these factors is infinitesimally small.

Are these issues handled differently in other countries?

In the U.K., they don’t have experts that are hired from one side or the other. The court appoints experts, who come up with an opinion that the court will use or decide not to use. There’s research that demonstrates that you have an implicit bias as an expert toward the side that hires you, no matter how much you try to put that out of your mind. This notion that we’re having objective science in the courtroom is wrong.