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Posted: **Thu Aug 22, 2019 7:23 am**

https://www.nist.gov/sites/default/file ... g_2019.pdf

I saw this on LinkedIn of all places...

Posted: **Thu Aug 22, 2019 7:56 am**

Maybe Ed can scoop this up and get it linked on his site?

Posted: **Fri Aug 23, 2019 1:10 pm**

I guess I'm somewhat confused on a couple elements of, and the implications of this document:

pg8 and 9 wrote:
• Five conclusion scale
• Source Exclusion
• Support for different sources
• Inconclusive/Lacking Support
• Support for same source
• Source Identification

• Source Identification: • Strongest degree of association between two friction ridge impressions • Expressed as a “strength of evidence” statement

• Source Identification: The strongest degree of association between two friction ridge impressions. It is the conclusion that the observations provide extremely strong support for the proposition that the impressions originated from the same source and extremely weak support for the proposition that the impressions originated from different sources.

• Source Identification is reached when the friction ridge impressions have corresponding ridge detail and the examiner would not expect to see the same arrangement of details repeated in an impression that came from a different source.

• Qualifications & Limitations: An examiner shall not assert that a source identification is the conclusion that two impressions were made by the same source or imply an individualization to the exclusion of all other sources.

A plain reading and implications of these slides are:

1) Conclusions are strength of associations between two prints and Source Identification does not mean source identification, it just means Extremely Strong Support. Exclusion must likewise be Extremely Strong Support for different sources.

2) The basis for Extremely Strong Support for same source is the expectation of the Examiner (..the examiner would not expect to see...)

So, my question is first, why would the language change for the upper and lower registers of the scale to mean something other than what the plain English means?

And secondly, how is something like this scale going to handle:
-limiting cases like Close Non Matches which show both support in two different directions?
-Error like the Mayfield Bum-ID where two different entities were making cases for support?
-thresholds where linear ACE-V is going to weigh Examiner expectations differently (since that's a basis for a conclusion)?

Posted: **Sat Aug 24, 2019 4:00 am**

Seriously, whatever happened to a trained and experienced expert, tested to establish competency and proficiency, offering an opinion?
Was the rate of erroneous identifications so high that we had to scrap that whole concept?

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