I mean, people have been convicted based on completely BS forensic 'science' that's little more than eyeball pattern matching with little to no basis in statistics.

http://www.slate.com/articles/news_and_politics/jurisprudenc...

This is a dangerously uneducated opinion. There is a long history of people being imprisoned on questionable forensic science. They should teach the history of hair analysis in school, because it's a tremendous tragedy.

https://www.theguardian.com/us-news/2015/apr/21/fbi-jail-hai...

He basically said "the butcher did it" and the guy immediately confessed. Certainly it didn't have to hold up in court in this case. :-)

The article doesn't say "immediately", and false confessions do occur, unfortunately.

I hope you're right, that it's just one tool to help direct an investigation, and that the confession was true, but I'm not entirely convinced by this article.

It starts by claiming he can tell "whether the knot-tier was left- or right handed, skilled or novice at knot tying, and in some cases, whether the crime was premeditated", but only a couple specific stories are given, and one was a knot which "people wouldn’t know of outside of the butcher trade", which is much more obvious and grounded than the earlier claims.

Of the first 14 Google Image results for "square knot" (before it starts returning other things), 8 tie it one way, and 6 tie it the other way -- and as I scroll down, this ratio seems pretty consistent. He claims for a right-handed person "the knot will almost certainly be formed right handed", but at first glance it seems much closer to 50/50.

He may not have claimed it, but when you stand in front of a jury and say something to the extent of "I'm an expert in knot analysis. This is the analytic system I employed to reach this particular conclusion" the implication to a jury of laymen is that you've employed a scientific method of some sort.

> He may not have claimed it, but when you stand in front of a jury and say something to the extent of "I'm an expert in knot analysis. This is the analytic system I employed to reach this particular conclusion" the implication to a jury of laymen is that you've employed a scientific method of some sort.

This is rather an argument against a jury of laymen.

And yet that is what is mandated in the constitution.

> And yet that is what is mandated in the constitution.

I don't live in the USA and am not US citizen - many HN readers don't either :-)

It can be used as an argument against both. But that's irrelevant to a discussion about what the presentation of this evidence says to a jury.