Advances in Fingerprint Technology.pdf

fingerprint was isolated. This area was chosen as it was the average area found
in a set of 300 latent fingerprints. The simulated latent prints, each actually
a subset of the original electronic fingerprint record, were then compared
against each of the 50,000 full fingerprint records.
The same software was used to compare fingerprints, compute scores,
and consolidate the scores. The same statistical analysis was performed.
As with the first experiment, examination of the Z scores from the nonidentical
prints revealed a number of unusually high scores. These included
the four same-finger, different print comparisons discovered in the first
experiment, here showing Z scores of 8.00, 7.58, 8.01, and 8.38. Additionally,
another same-finger, different print pair was discovered, showing Z scores of
3.91 and 5.85.
Similar to the first experiment, these different prints from the same finger
were excluded from the analysis. Meagher, Budowle, and Ziesig proceeded
by grouping the Z score results according to the number of minutiae in the
simulated latent print and a chart was prepared of Z score vs. minutia count.
The highest Z scores for the non-identical print comparisons were plotted,
along with the Z scores for the comparisons of the simulated latent prints
with their corresponding original electronic record (under the hypothesis of
equal means).
Meagher, Budowle, and Ziesig concluded by calculating probabilities that
simulated latent prints with a particular minutia count would be identical
to a subset of any particular fingerprint. For a simulated latent with a small
number of minutiae (c.f. 4) they stated that the probability was less than
1/10 27 , decreasing with larger numbers of minutiae (c.f. 18) to 1/10 97 (the
same probability offered in the first experiment for complete rolled fingerprints).
Following their earlier analysis, Meagher, Budowle, and Ziesig compared
the larger (4 minutia) probability with the world population, concluding that
the chance of any two (small) minutia subsets from any (different) fingerprints
on earth being identical was 59/10 18 .
Discussion of the Meagher, Budowle, and Ziesig Model
The Meagher, Budowle, and Ziesig model has been discussed by Stoney 62-64
and by Wayman. 65 The major issue with this model is that, with the exception
of the excluded data, the Meagher, Budowle, and Ziesig experiments do not
include comparing two different prints of the same finger with each other.
All actual fingerprint comparisons have this aspect, and every fingerprint
examiner knows that no two impressions from the same finger are exactly
alike. There would never be an occasion to compare a single fingerprint with
itself.