Appendix C — The Junk-Science Watchlist

Appendix C — The Junk-Science Watchlist

What the 2009 National Academy of Sciences report and the 2016 PCAST report actually concluded about "forensic" techniques. Distrust confident courtroom certainty in the un-validated ones.

Comparatively well-founded (with real limits):

• Single-source DNA analysis — the one technique the NAS report exempted from its blanket criticism; still vulnerable to contamination, transfer, and complex-mixture interpretation.
• Latent fingerprints — foundationally validated by PCAST, but with a real, measurable examiner error rate (see: Brandon Mayfield) — not the zero it was long claimed to be.

Treat with heavy scepticism (validity not established per PCAST 2016 / criticised by NAS 2009):

• Bite-mark analysis — widely discredited; linked to multiple DNA exonerations.
• Microscopic hair comparison — an FBI/DOJ/Innocence Project review found flawed testimony in the great majority of cases examined.
• Complex-mixture DNA (three or more contributors, low-template) — far shakier than single-source.
• Firearms & tool-mark "matching", footwear, bloodstain-pattern analysis — foundational validity not established.
• Traditional arson indicators — much of the old "accelerant" folklore has been debunked (see: Cameron Todd Willingham).

The rule of thumb: the more certain the courtroom claim ("a match, to the exclusion of all others"), the more you should ask for the measured error rate. A real science can give you one. A junk science offers confidence instead.