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...and even more "scientific" methods like finger-prints or DNA evidence. These methods of investigation are often portrayed in popular media as 100% effective

...and even more "scientific" methods like finger-prints or DNA evidence. These methods of investigation are often portrayed in popular media as 100% effective in providing proof, however their real rates of effectiveness are quite a bit lower. Is there hard data on the failure rate of fingerprint evidence? That's quite interesting.

wavefunction 13y ago
Well, that's the thing, I don't think (to my knowledge, basically) that they even track such things. Finger-print analysis isn't even standardized, apparently. Brandon Mayfield is one example of a high-level failure in such analysis. He was implicated in the Madrid bombings by a finger-print and thus faced serious international terrorism charges despite being completely innocent. Here's an article that touches on some of the issues, and also mentions some of Brandon Mayfield's experience: http://www.cbsnews.com/8301-3445_162-4069140.html http://www.cbsnews.com/8301-3445_162-4069140.html A finger-print analyst in the linked article claims 98% efficacy, though there is no data to back up that number. With no standards and no apparent statistics to back up their successes and failures.
woodson 13y ago
Please understand that there are much more relevant factors to the use of fingerprint to fingermark comparison evidence in court than their ability to discriminate under ideal laboratory conditions. For some information see: National Institute of Standards and Technology, National Institute of Justice, February 2012 report: "Latent Print Examination and Human Factors: Improving the Practice through a Systems Approach" (http://nij.gov/pubs-sum/latent-print-human-factors.htm http://nij.gov/pubs-sum/latent-print-human-factors.htm) In general there is a move towards probabilistic assessment of the strength of evidence (likelihood ratios), which offers a logically correct way of approaching problems in the forensic evaluation of evidence.
monkeyspaw 13y ago
According to popular mechanics (http://www.popularmechanics.com/science/health/forensics/4325797 http://www.popularmechanics.com/science/health/forensics/432...): 'No studies have proved definitively that fingerprints are unique. Likewise, it is unclear if prints change over time or vary depending on the amount of pressure applied. Statistical models and pattern-recognition software could go a long way toward answering these questions. Additionally, research is needed to expose error rates. The ACE-V method depends on two or more examiners reaching the same subjective conclusion, but doesn't require them to reach it the same way. In one recent experiment, veteran examiners looking twice at the same print came to different conclusions each time. "

wavefunction 13y ago

Well, that's the thing, I don't think (to my knowledge, basically) that they even track such things. Finger-print analysis isn't even standardized, apparently. Brandon Mayfield is one example of a high-level failure in such analysis. He was implicated in the Madrid bombings by a finger-print and thus faced serious international terrorism charges despite being completely innocent. Here's an article that touches on some of the issues, and also mentions some of Brandon Mayfield's experience: http://www.cbsnews.com/8301-3445_162-4069140.html http://www.cbsnews.com/8301-3445_162-4069140.html A finger-print analyst in the linked article claims 98% efficacy, though there is no data to back up that number. With no standards and no apparent statistics to back up their successes and failures.

woodson 13y ago

Please understand that there are much more relevant factors to the use of fingerprint to fingermark comparison evidence in court than their ability to discriminate under ideal laboratory conditions. For some information see: National Institute of Standards and Technology, National Institute of Justice, February 2012 report: "Latent Print Examination and Human Factors: Improving the Practice through a Systems Approach" (http://nij.gov/pubs-sum/latent-print-human-factors.htm http://nij.gov/pubs-sum/latent-print-human-factors.htm) In general there is a move towards probabilistic assessment of the strength of evidence (likelihood ratios), which offers a logically correct way of approaching problems in the forensic evaluation of evidence.

monkeyspaw 13y ago

According to popular mechanics (http://www.popularmechanics.com/science/health/forensics/4325797 http://www.popularmechanics.com/science/health/forensics/432...): 'No studies have proved definitively that fingerprints are unique. Likewise, it is unclear if prints change over time or vary depending on the amount of pressure applied. Statistical models and pattern-recognition software could go a long way toward answering these questions. Additionally, research is needed to expose error rates. The ACE-V method depends on two or more examiners reaching the same subjective conclusion, but doesn't require them to reach it the same way. In one recent experiment, veteran examiners looking twice at the same print came to different conclusions each time. "