To a lay person in a situation like this, how does the distinction you make (between bad science and an incompetent application) imply an actual difference? Parents got stripped of their children because of some "scientific" process that the court relied upon.

Bad execution can and should be improved upon. Bad science (eg, matching bullets to guns) needs to be thrown onto the trash heap of history.

The former can be debunked on a case by case basis. The latter needs to be categorically banned from judicial proceedings.

Are you saying that ballistic fingerprinting is entirely bullshit?

I don't know if that's what OP is saying, but it seems fair to say that it's at least enough bullshit that it should probably never be used as evidentiary.

The states who pioneered its adoption (New York and Maryland) have both abandoned it for being costly and ineffective. The FBI has abandoned comparative bullet lead analysis for similar reasons[1]. The National Academy of Sciences found the tests to be "full of holes", and that not enough study was being done to ensure its reliability, which was a finding that the United States President's Council of Advisors on Science and Technology under Obama concurred with.

The general consensus now seems to be this[2]:

> An understanding of the metallurgical principles operative in the melting/casting process as well as the data acquired for this study, indicate that any forensic conclusions which associate unknown bullets with the “same source”, and/or “same box” should fail most or all Daubert criteria.

[1] http://www.washingtonpost.com/wp-dyn/content/article/2007/11...

[2] https://www.sciencedirect.com/science/article/pii/S037907380...

>it seems fair to say that it's at least enough bullshit that it should probably never be used as evidentiary.

Doesn't this also apply to eyewitness testimony, if not many other forms of evidence?

Yes, ballistic fingerprinting was just brought up as an example.

There is some very serious issues with it, so many issues it can't be considered scientific, at least not yet.

https://en.wikipedia.org/wiki/Forensic_firearm_examination

>Further criticism came from the 2009 NAS report on the current state of various forensic fields in the United States. The report's section on firearm examination focused on the lack of defined requirements that are necessary in order to determine "matches" between known and unknown striations. The NAS stated that, "sufficient studies have not been done to understand the reliability and repeatability of the methods."[23]:154 Without defined procedures on what is and what isn't considered "sufficient agreement" the report states that forensic firearm examination contains fundamental problems that need to be addressed by the forensic community through a set of repeatable scientific studies that outline standard operating procedures that should be adopted by all firearm examiners.[23]:155 Another report issued in 2016 by the United States President's Council of Advisors on Science and Technology confirmed the NAS's findings, finding only one appropriately designed study that examined the rate of false positives and reliability amongst firearm examiners.[40]

It implies a difference in what their attitude ought to be the next tine they hear about 'hair testing' being used elsewhere...

Parent's had their children wrongly taken away from them. Depending on the age of the children, even if they're returned, that trauma will have a lifetime affect on them.

Who cares what those people think about "hair testing".

From a systemic perspective, we can't correct for bad science until better science disproves it and becomes common enough knowledge. Unless you're both a parent and a cutting edge scientist in the field being employed against you, this is true at an individual level too. Incompetent application can, with transparent processes, be investigated by the defending party/parent/lawyer and be argued against. Or if the investigation can't be completed until after the children have been seized, corrections can be made and damages can be pursued.

Hair analysis has been proven to be largely junk science.

That's a separate issue because Hair analysis is not inherently worthless. It was just assumed to be vastly more accurate than it actually was.

You can for example tell from a hair sample is not from the same person. IE blond hair vs black hair. You can't do the reverse and tell it is from the same person without DNA testing.

This isn't that kind of hair analysis - determining which person a hair found at the scene is from. This is looking for markers of drug and alcohol use in hair samples from a known person.

That was my point, but rereading my comment it really did not come across.

Basically, a different thing had been discredited in the past also involving testing hair. Which IMO is why people though testing hair was junk science vs. the lab not doing their job properly.

That said, I also think testing hair for drugs is so inaccurate to basically be worthless.

Someone can do junk science irrespective of the field and it has no bearing on the field. There's junk science dna testing. Junk science physics. Everything and anything can be junk science if you apply yourself and try real hard.