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Measuring what latent fingerprint examiners consider sufficient information for individualization determinations.

Ulery BT, Hicklin RA, Roberts MA, Buscaglia J - PLoS ONE (2014)

Bottom Line: Latent print examiners use their expertise to determine whether the information present in a comparison of two fingerprints (or palmprints) is sufficient to conclude that the prints were from the same source (individualization).Examiners' counts of corresponding minutiae were strongly associated with their own determinations; however, due to substantial variation of both annotations and determinations among examiners, one examiner's annotation and determination on a given comparison is a relatively weak predictor of whether another examiner would individualize.The extensive variability in annotations also means that we must treat any individual examiner's minutia counts as interpretations of the (unknowable) information content of the prints: saying "the prints had N corresponding minutiae marked" is not the same as "the prints had N corresponding minutiae." More consistency in annotations, which could be achieved through standardization and training, should lead to process improvements and provide greater transparency in casework.

View Article: PubMed Central - PubMed

Affiliation: Noblis, Falls Church, Virginia, United States of America.

ABSTRACT
Latent print examiners use their expertise to determine whether the information present in a comparison of two fingerprints (or palmprints) is sufficient to conclude that the prints were from the same source (individualization). When fingerprint evidence is presented in court, it is the examiner's determination--not an objective metric--that is presented. This study was designed to ascertain the factors that explain examiners' determinations of sufficiency for individualization. Volunteer latent print examiners (n = 170) were each assigned 22 pairs of latent and exemplar prints for examination, and annotated features, correspondence of features, and clarity. The 320 image pairs were selected specifically to control clarity and quantity of features. The predominant factor differentiating annotations associated with individualization and inconclusive determinations is the count of corresponding minutiae; other factors such as clarity provided minimal additional discriminative value. Examiners' counts of corresponding minutiae were strongly associated with their own determinations; however, due to substantial variation of both annotations and determinations among examiners, one examiner's annotation and determination on a given comparison is a relatively weak predictor of whether another examiner would individualize. The extensive variability in annotations also means that we must treat any individual examiner's minutia counts as interpretations of the (unknowable) information content of the prints: saying "the prints had N corresponding minutiae marked" is not the same as "the prints had N corresponding minutiae." More consistency in annotations, which could be achieved through standardization and training, should lead to process improvements and provide greater transparency in casework.

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Detail of Figure 5 for the 39 image pairs that had median corresponding minutia counts between 6 and 9.5, with the addition of box plots showing interquartile range, minima, and maxima.(n = 452 responses; 6 to 16 responses per image pair.)
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pone-0110179-g006: Detail of Figure 5 for the 39 image pairs that had median corresponding minutia counts between 6 and 9.5, with the addition of box plots showing interquartile range, minima, and maxima.(n = 452 responses; 6 to 16 responses per image pair.)

Mentions: Figure 5 shows the association between corresponding minutia counts and determinations, as well as the reproducibility of counts and determinations among examiners. The strong association between examiners' minutia counts and their own determinations shown in Figure 3B is seen here as a color change in the vertical dimension. Figure 6 shows a subset of this data to more clearly reveal the interexaminer variability on each image pair. For most image pairs (x-axis), we see substantial interexaminer variability in both the corresponding minutia counts (vertical spread) and determinations (color). This extensive variability means that we must treat any individual examiner's minutia counts as interpretations of the (unknowable) information content of the prints: saying “the prints had N corresponding minutiae marked” is not the same as “the prints had N corresponding minutiae.” The variability also implies that one examiner's minutia count is a weak predictor of another examiner's determination: for example, while we might have assumed that having one examiner mark 13 or more corresponding minutiae and individualize would guarantee that any other examiner would also individualize, that is not true; most of the mated image pairs had one or more examiners mark 13 or more corresponding minutiae. Appendix S15 includes additional charts clarifying some of these relations and showing results from the Analysis phase. See Appendix S16 for corresponding data on the nonmated pairs.


Measuring what latent fingerprint examiners consider sufficient information for individualization determinations.

Ulery BT, Hicklin RA, Roberts MA, Buscaglia J - PLoS ONE (2014)

Detail of Figure 5 for the 39 image pairs that had median corresponding minutia counts between 6 and 9.5, with the addition of box plots showing interquartile range, minima, and maxima.(n = 452 responses; 6 to 16 responses per image pair.)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4221158&req=5

pone-0110179-g006: Detail of Figure 5 for the 39 image pairs that had median corresponding minutia counts between 6 and 9.5, with the addition of box plots showing interquartile range, minima, and maxima.(n = 452 responses; 6 to 16 responses per image pair.)
Mentions: Figure 5 shows the association between corresponding minutia counts and determinations, as well as the reproducibility of counts and determinations among examiners. The strong association between examiners' minutia counts and their own determinations shown in Figure 3B is seen here as a color change in the vertical dimension. Figure 6 shows a subset of this data to more clearly reveal the interexaminer variability on each image pair. For most image pairs (x-axis), we see substantial interexaminer variability in both the corresponding minutia counts (vertical spread) and determinations (color). This extensive variability means that we must treat any individual examiner's minutia counts as interpretations of the (unknowable) information content of the prints: saying “the prints had N corresponding minutiae marked” is not the same as “the prints had N corresponding minutiae.” The variability also implies that one examiner's minutia count is a weak predictor of another examiner's determination: for example, while we might have assumed that having one examiner mark 13 or more corresponding minutiae and individualize would guarantee that any other examiner would also individualize, that is not true; most of the mated image pairs had one or more examiners mark 13 or more corresponding minutiae. Appendix S15 includes additional charts clarifying some of these relations and showing results from the Analysis phase. See Appendix S16 for corresponding data on the nonmated pairs.

Bottom Line: Latent print examiners use their expertise to determine whether the information present in a comparison of two fingerprints (or palmprints) is sufficient to conclude that the prints were from the same source (individualization).Examiners' counts of corresponding minutiae were strongly associated with their own determinations; however, due to substantial variation of both annotations and determinations among examiners, one examiner's annotation and determination on a given comparison is a relatively weak predictor of whether another examiner would individualize.The extensive variability in annotations also means that we must treat any individual examiner's minutia counts as interpretations of the (unknowable) information content of the prints: saying "the prints had N corresponding minutiae marked" is not the same as "the prints had N corresponding minutiae." More consistency in annotations, which could be achieved through standardization and training, should lead to process improvements and provide greater transparency in casework.

View Article: PubMed Central - PubMed

Affiliation: Noblis, Falls Church, Virginia, United States of America.

ABSTRACT
Latent print examiners use their expertise to determine whether the information present in a comparison of two fingerprints (or palmprints) is sufficient to conclude that the prints were from the same source (individualization). When fingerprint evidence is presented in court, it is the examiner's determination--not an objective metric--that is presented. This study was designed to ascertain the factors that explain examiners' determinations of sufficiency for individualization. Volunteer latent print examiners (n = 170) were each assigned 22 pairs of latent and exemplar prints for examination, and annotated features, correspondence of features, and clarity. The 320 image pairs were selected specifically to control clarity and quantity of features. The predominant factor differentiating annotations associated with individualization and inconclusive determinations is the count of corresponding minutiae; other factors such as clarity provided minimal additional discriminative value. Examiners' counts of corresponding minutiae were strongly associated with their own determinations; however, due to substantial variation of both annotations and determinations among examiners, one examiner's annotation and determination on a given comparison is a relatively weak predictor of whether another examiner would individualize. The extensive variability in annotations also means that we must treat any individual examiner's minutia counts as interpretations of the (unknowable) information content of the prints: saying "the prints had N corresponding minutiae marked" is not the same as "the prints had N corresponding minutiae." More consistency in annotations, which could be achieved through standardization and training, should lead to process improvements and provide greater transparency in casework.

Show MeSH