Chris McLean (Unregistered Guest)
Posted From: cow-198-163-45-80.winnipeg.ca
|Posted on Thursday, August 05, 2010 - 09:33 am: ||
Read QUANTITATIVE-QUALITATIVE FRICTION RIDGE ANALYSIS BY DAVID ASHBAUGH. Basically, fingerprint identification historically was based on a specific number of ridge characteristics (2nd level detail - aka Galton details). In North America this threshold was set somewhere around the ten or twelve ridge characteristic mark. This number was arrived at (and still is) through what can best be described as an educated conjecture, based on best observations, as to when there was thought to be enough detail in agreement to feel safe an error could not be made.
These thesholds are set by peer groups and forensic managers of fingerprint examiners in the country of origin.
Keep in mind that there is much more being compared than 2nd level detail, which is why in 1973 the IAI, based on a three year study found "no valid basis exists for requiring that a pre-determined minimum of friction ridge characteristics must be present in two impressions in order to establish positive identification"
If you aren't already doing so, read Ashbaugh's book.
D. Jackson (Froghog)
Post Number: 2
|Posted on Tuesday, August 03, 2010 - 06:06 pm: ||
I am in the process of training in-house to become a latent print examiner, and I am completely stuck on this one question! In my research I have found that Germany requires a minimum of 12 points for identification, and Argentina 30 points. What I am trying to find out is - required by WHOM? Is it federal, state, city, etc. Any help on this is greatly appreciated! Thank you.