https://www.washingtonpost.com/opini...rce=reddit.com
Last September, the D.C. Superior Court restricted the testimony of a prosecution ballistics expert in a felony case. I want to draw some attention to the opinion, which I haven’t seen written up elsewhere, because it is one of the best decisions I have read in response to a challenge to the scientific validity of forensic evidence, particularly in a criminal case.
As I’ve written here ad nauseam, judges are entrusted to be the gatekeepers of good and bad science in the courtroom. By and large, they’ve performed poorly. Judges are trained to perform legal analysis, not scientific analysis, and law and science are two very different fields. Science is forward-looking, always changing and adapting to discoveries and new empirical evidence. The law, by contrast, puts a premium on consistency and predictability. It relies on precedent, so courts look to previous courts for guidance and are often bound by prior decisions.
By and large, judges have approached their task of scientific analysis just as we might expect them to: They have tried to apply it within a legal framework. This means when assessing whether a given field of forensics is scientifically reliable, judges tend to look to what previous courts have already determined. And when confronted with a new field, they tend to err on the side of relying on our adversarial system — they let the evidence in but also let the defense call its own experts to dispute the prosecution’s witness. The problem here is that by simply admitting the evidence, the courts lend it an air of legitimacy. Once the evidence is allowed in, whether jurors find it convincing tends to come down to which witness is most persuasive. State’s witnesses are often seen as unbiased and altruistic, while jurors tend to see defense witnesses as hired guns. And the set of skills it takes to persuade a jury isn’t necessarily the same skill set of a careful and cautious scientist. Indeed, the two are often in conflict.
Bookmarks