Advances in Fingerprint Technology.pdf

the probability of two different prints being ‘in common,’ as previously and
unreasonably defined, to be one in 10 97 . This number, 10 97 , is extremely
large…. It is possible that in the entire future of mankind there will never
be 10 97 fingerprints. Yet, the government is comfortable predicting the fingerprints
of the entire history and future of mankind from a sample of 50,000
images, which could have come from as few as 5000 people. They have disguised
this absurd guess by claming reliance on statistical estimation.”
Meagher, Budowle, and Ziesig also incorrectly applied their probability
to the world population. After calculating their probability that a non-mate
fingerprint would match any particular fingerprint, they multiplied this
probability by the world population to arrive at “the approximate chance that
any two fingerprints on earth” would be identical. This is a basic error. The
point is often illustrated in basic statistics courses by calculating the probability
that two persons in a classroom of, say 30, would have the same
birthday. Although there is a 1/365 chance of a match between two people,
there is a more than 70% chance that there will be one or more shared
birthdays among 30 people. This is a minor point, however, given the far
more fundamental conceptual errors in these experiments.
The Meagher, Budowle, and Ziesig model is extraordinarily flawed and
highly misleading. It was specifically designed to “prove the uniqueness” of
fingerprints in a Daubert hearing, and incorporates a profound ignorance of
both forensic science and statistics. Perhaps the most remarkable aspect of
these experiments is that they continue to be introduced in such hearings.
Whether or not the courts ultimately feel there is any question about fingerprints
meeting the conditions of Daubert, there can be no doubt that the
Meagher, Budowle, and Ziesig model itself could not.
Conclusions
From a statistical viewpoint, the scientific foundation for fingerprint individuality
is incredibly weak. Beginning with Galton and extending through
Meagher, Budowle, and Ziesig, there have been a dozen or so statistical
models proposed. These vary considerably in their complexity, but in general
there has been much speculation and little data. Champod’s work is perhaps
the exception, bringing forth the first realistic means to predict frequencies
of occurrence of specific combinations of ridge minutiae. None of the models
has been subjected to testing, which is of course the basic element of the
scientific approach. As our computer capabilities increase, we can expect that
there will be the means to properly model and test hypotheses regarding the
variability in fingerprints. The most difficult challenge will remain the growth
and acceptance of scientific practices in the fingerprint profession itself. We