MADISON, N.J.

AMERICA’S FORENSICS system, the part of our criminal-justice system responsible for scientific examinations of crime-scene evidence like fingerprints and DNA, is rife with errors. While some mistakes, such as botched tests or erroneously interpreted results, are inevitable, recent national statistics reveal that current error rates are needlessly high.

The root of our national forensics problem isn’t lack of oversight. Rather, it’s monopoly. Once evidence goes to a given lab or facility, it is unlikely to be examined by any other lab or facility. That makes it more likely mistakes will slip through undetected.

With the right reforms, we can break down that monopoly and create a working system of checks and balances. Here a few essential steps to a better system:

• Rivalrous redundancy. A jurisdiction should contain several competing forensic labs. Sometimes evidence should be randomly chosen for multiple testing. No lab would know when a given piece of evidence was being examined by another lab, so it would have a greater incentive to find the truth and apply rigorous scientific standards. More fundamentally, redundant testing increases the chance that honest errors would be caught and the underlying problems fixed.

• Independence. Coroners and forensic scientists often have a pro-police bias, thinking of themselves as a part of the prosecution team. To establish their independence from police and prosecutors, crime labs should be organized by the courts, not the cops.

• Statistical review. Labs should be subject to statistical comparison. Any lab with a statistically unusual profile should be examined to fix the problem or expose a best practice others should imitate.

• Masking. Forensic scientists should be shielded from what psychologists call “domain-irrelevant information.” Knowing whether the case at hand is, for example, a murder or a burglary exposes a fingerprint examiner to a powerful unconscious bias: The emotional nature of a murder case tends to make the scientist eager to get a killer off the streets and more likely to declare a match.

• Forensic vouchers. An indigent suspect on trial should have the right to forensic counsel and he should be able to select his own forensic counsel using a government-issued voucher to pay for it. The forensic scientist who accepts the case would later redeem the voucher at the courthouse, receiving his paycheck from an officer of the court. Such a system would give forensic counselors to the poor an incentive to provide high-quality services.

• Task separation. A forensic scientist who conducts, say, a blood test should not decide whether the test excludes the suspect. The interpretation of the test should be made by other forensic scientists. When a lab report comes back, it should be transmitted to two forensic scientists — one representing the prosecution and one representing the defense — for interpretation. That way, fewer errors of interpretation will go unchallenged.

• Privatization. Private labs are subject to civil liability and administrative fines for poor performance. They therefore have stronger financial incentives than publicly owned enterprises to provide good and reliable work.

These changes would reduce the costs of the criminal-justice system. The extra cost of multiple forensic tests is dwarfed by the savings associated with reduced jail time for the wrongly convicted. For example, the $100 cost of a fingerprint examination is one one-thousandth of the cost of incarcerating a wrongly convicted felon who has been given the average sentence of almost five years.

Roger Koppl is the director of Fairleigh Dickinson University’s Institute for Forensic Science Administration. This piece is adapted from an article he wrote for Reason magazine.