I wonder if whoever is supplying evidence via tests should be forced to (blindly) apply the tests to people other than the defendant. If your test says some random sample is more likely match than I am, it's very weak evidence.
there are certainly a number of forensic fields which are garbage.
other portions are fine, and are effectively analytical chemistry applied to legal cases. are you aware of a lot of double blind studies in analytical chemistry? what would that even mean?
How much of the conclusions drawn from these investigative techniques are justified entirely by analytic chemistry, and how much goes beyond that? Using an example from a related article, there's a substantial difference between being able to say what's the chemical element composition of a particular bullet and being able to identify the particular manufacturing facility and batch it came from. The latter relies on a whole lot of assumptions about the ammunition industry.