Since it was introduced in the 1980s, DNA evidence has become a “gold standard” of U.S. courtrooms, leading to the convictions—and exonerations—of thousands of accused criminals. But experts struggle to analyze degraded or contaminated samples, and many have started to use sophisticated probabilistic genotyping software to estimate the likelihood that a suspect’s DNA matches DNA at the crime scene. Such so-called forensic algorithms are far from rare: Increasingly, they’re used to estimate matches for everything from fingerprints to gun barrels to faces in security camera footage.
Defense attorneys rarely have access to the source code or other information that would explain how such software—which is often proprietary—works. That’s because companies fear providing it would expose trade secrets or other kinds of intellectual property. But the opacity has raised concerns about fairness and transparency.
Last week, Representative Mark Takano (D–CA) introduced legislation that would make it easier for defendants facing federal criminal charges to gain access to forensic algorithms, and further require the makers of computational forensic software to meet minimum standards set by the National Institute of Standards and Technology (NIST).
ScienceInsider caught up with Takano to discuss the new bill. This interview has been edited for brevity and clarity.
Q: What problems would this bill solve?
A: What we know is that people are often convicted with probabilistic models being the sole evidence in the case. People can be put in jail, they can even lose their lives [over just] this form of circumstantial evidence. And what we also know is that companies that put forward these technologies do not want to open up the source code or explain much about the underlying data and have it questioned by the defense. We think there’s a fundamental problem with this. Intellectual property rights should not be able to trump due process.
Q: Which of these forensic technologies are you most worried about?
A: DNA evidence [from] probabilistic genotyping software for DNA analysis. It has the appearance of being ironclad truth, in the same way that many decades ago … a lie detector test [did]. The trappings of science may lead to [false certainty] for juries and judges. It’s fully appropriate, and actually necessary, for juries and judges to understand the limits of technology and how it works.
Q: This bill calls on NIST to test forensic software. What would it be testing?
A: Obviously, they would have their analysts look at the technology to gauge what the limitations are, what the possibilities are, and [they would] look at what the science out there says about data and how these algorithms work. We would encourage them to [ask companies]: “Have you tested these out, and can you show us data? Is there an error rate that shows a disproportionate impact on minorities, with, for example, minorities being falsely identified?” We think that every angle ought to be looked at in terms of how these systems might fail.
Q: What inspired this bill?
A: I talk a lot about my family’s incarceration during World War II and Japanese American internment. What’s the connection there? It has to do with privacy rights, it has to do with due process. At the same time, this helps keep the government current with technology and helps Congress understand the latest technology. The danger is that—whether it’s voting systems that look bright and shiny or nice little black boxes that spit out a result—citizens and juries and judges and prosecutors and defense lawyers [don’t] understand how these systems work.
Q: What challenges does this bill face?
A: I think it’s that general issue of trying to get members’ attention, colleagues’ attention and getting the key subcommittee members to pick it up and understand the underlying issue. I think these are all very achievable sorts of things. The other barrier is that the [House of Representatives] judiciary committee has a lot on its plate right now. [Takano was referring to impeachment investigations against President Donald Trump.] It’s bigger attention-getting topics that may be my impediment at this point. But I think … this is a case where the American people understand [the need], so the [effort] could be in a bipartisan manner.