> Does any one know of a paper or court ruling that specifically states by not following the methodology in 921 could lead to a increase rate of error.
This was probably a rhetorical question, Jim?

(As I see it) the problem is obvious;
an error rate can only be determined if you know the correct answer
- this is currently usually the call of the responding FI,
Unless we have fire scenes attended by multiple FI's,
the 'correct' finding thoroughly debated and decided upon in a court of law,
and the non 921-adhering FI's then counted, tallied and reported - who would know?


A similar issue arises when laboratory accreditors start asking for error rates/standard deviations etc.
This is fine for DNA-analysis with a verifiable "1 in 17 billion"-type statistics,
or drug analysis with demonstrable quantitative values with a "RDS <1.2%".
How do you quantify the 'certainty' of fire-debris analysis (see ASTM E1618) or Fire Investigation?

I do recall some structured burn testing where a class of FI's were called in to make their (respective) calls;
as I remember the results were worrying...