Friday, 29 November 2013

Maryland v. King: The Dissent's Ten Second Rule

The four dissenting Justices in Maryland v. King insisted that DNA databases and fingerprint databases are as different as night and day. As NYU Law Professor Erin Murphy put it:
Most powerfully, Justice Scalia explained (partially through the use of a chart) why fingerprinting differed dramatically from DNA typing. He observed that known fingerprints are not “systematically compared” with latent prints from unsolved crime scenes (in contrast to DNA), and even if so, courts have never approved such action. He also observed that while fingerprinting may not even be a “search,” analysis of genetic code certainly is.
(Murphy 2013, p. 166, note omitted). Relying solely on Justice Scalia's "powerful" assurances, she adds that
Police have never routinely collected or used photographs or prints for random crime-solving purposes; both were always mainly for identification of persons already suspected of a crime (i.e., individualized suspicion).114 We know this intuitively: how common are newspaper headlines about thirty-year-old cases solved through “cold hit” fingerprint or mug shot matches, or exonerations based on a hit to a fingerprint or photograph newly uploaded to the database?
114. See King, 133 S. Ct. at 1987-88 (Scalia, J., dissenting). Indeed, police could not have used photos or fingerprints for random crime-solving even if they had wanted to, since it was not until twenty or so years ago--when large biometric databases were developed--that it was even possible to conduct a random automated comparison between known files and crime scene samples.
Id. at 177-78.There are several problems with Justice Scalia's claims as well as this gloss on them.

I. What Does the Possibility that Fingerprinting Might Not Be a "Search" Prove?

To begin with, the claim that fingerprinting might not be a search as that word is used in the Fourth Amendment is not proof of any "dramatic" difference between fingerprinting and DNA typing.1/ Given Justice Scalia's emphasis on the invasion of physical space as the touchstone for defining a search in recent cases, e.g., United States v. Jones, 132 S.Ct. 945 (2012), how could he maintain that taking control of a person's fingers to rub them on an inked pad and then onto cardboard paper, or to press them against a scanner, is not a search? And even if he were to classify fingerprinting as something less than a search, would not he have do the same for DNA collection if Maryland substituted pressing just one digit onto a sticky pad to recover cells (instead of rubbing a swab along the inside of a cheek)?2/

More fundamentally, the dissent's declaration that one invasion of personal security (fingerprinting) might not rise to the level of a search while another (DNA typing) clearly does assumes what must be proved--that the two are indeed "dramatically" different. Because slight differences can lead to one legal classification (a "search") as opposed to the other (not quite a search), the fact that the Supreme Court has never adjudicated whether fingerprinting is a search does little to demonstrate any stark contrast between that practice and DNA swabbing.

II. How Often Are Suspicionless Fingerprint Database Trawls Conducted?

Moving to the part of the dissenting opinion that does offer an actual distinction (as opposed to a legal label that might (or might not) flow from some unarticulated differences), let us consider Justice Scalia's basic distinction and Professor Murphy's remarks about it. According to the dissent, it is critical that “‘[l]atent prints’ recovered from crime scenes are not systematically compared against the database of known fingerprints, since that requires further forensic work.” 133 S. Ct. at 1987 (note omitted). And citing only Justice Scalia's opinion, Professor Murphy (p. 166) concurs that "[p]olice have never routinely collected or used photographs or prints for random crime-solving purposes ... ."

Justice Scalia provides no particular support for the proposition that arrestee fingerprints are not systematically compared to latent prints, and it is apparent that police often compare latent prints to those from arrestees to generate investigative leads—just as Maryland did with the DNA in King. Let me elaborate on each of these points.

A. Justice Scalia's Ten-second Rule

To support the claim that fingerprints are not used like DNA profiles--to forge previously unsuspected links between unsolved crimes and arrestees--the dissenting opinion cites only one publication. It is an FBI webpage entitled "Privacy Impact Assessment: Integrated Automated Fingerprint Identification System (IAFIS)/Next Generation Identification (NGI) Repository for Individuals of Special Concern (RISC)." To the extent that this webpage is on point, it contradicts the four dissenting Justices' claim. The page only discusses a special database for individuals who may or may not have been arrested. Specifically, RISC “consist[s] of records of known or appropriately suspected terrorists, wanted persons, registered sexual offenders, and (potentially) other categories of heightened interest warranting more rapid responses to inquiring criminal justice users.” Id. § 1.2. The purpose of RISC is “to support rapid biometric searches ... in time-critical situations.” Id. § 1.1. The idea is that “first responder law enforcement officials in the course of their interaction with potential suspects” will acquire the suspect’s fingerprints with a mobile scanner and send them to the FBI. Within ten seconds, the FBI’s computer will advise the submitting agency whether there is a probable match to one of the “individuals of special concern.” Id. At the same time, the FBI will query its “Unsolved Latent File (ULF).” Id. This “cascaded search of the ULF may take considerably more time than the RISC search,” but “if a RISC submission hits on a record in the ULF, ... the ULF record submitter will receive notification of a potential match.” Id.

The dissenting Justices seem to think that the FBI’s notice that “searches of the ‘Unsolved Latent File’ may ‘take considerably more time’” than ten seconds means that the FBI does not perform these slower searches. King, 133 S. Ct. at 1987 n. 4. I am reminded of the five-second rule for consuming food that falls on the floor. Folklore has it that if the period of contact is less than five seconds, contamination is not worth worrying about. Of course, the "rule" is silly. (See Dawson et al. 2007).

The dissent's ten-second rule is not much better. The FBI’s description of RISC is clear (once one cuts through the bureaucratic jargon). Every time the police submit a suspect’s prints for a RISC check, the prints also are checked against those of “unknown persons whose latent fingerprints have been retrieved from locations, property, or persons associated with criminal activity or related to criminal justice or authorized national security investigations.” Id. If this is not a systematic use of suspects’ prints to associate them with unsolved crimes, nothing is.

B. Better Indications of Fingerprint Database Practice

RISC is just one database, and it is not used for routine, station-house bookings. In those situations, whether and when arrestee fingerprints are checked against latent prints from unsolved crimes varies by jurisdiction. In California, “new incoming latent prints from unsolved crimes are routinely searched against arrestee booking prints, regardless of the arrest disposition (e.g., whether or not the arrestee ultimately was convicted of the offense) in the Automated Latent Print System (ALPS) database.” Cal. Dep’t of Just. (2013). Conversely, arrestee prints are checked against the ALPS database to generate investigative leads whenever they do not match known prints already on file. Id. These new arrestee-to-ALPS trawls occurred more than 25% of the time in recent years. Id.

A brief on behalf of California (and every other state) informed the Court of some of these facts. (Brief for the States 2013, pp. 17–18). The dissent’s citation to the largely inapposite RISC system, its misreading of how that system works, and its failure to consider the widespread use of automated-fingerprint-identification systems and to present any information about manual searches conducted before the 1980s or 1990s (see below) partakes more of advocacy than accuracy.

But California is just one state. I have no data on whether other states are more or less systematic in using automated fingerprint identification systems (AFIS's) with their databases or with the national one, to solve crimes. I have requested information on the use of the IAFIS database administered by the FBI from that agency, but I have yet to receive a reply. Could Professor Murphy's intuition that latent prints rarely are searched against the fingerprints on file from arrestees--and that such searches never happened "until twenty or so years ago" be correct?

It seems most unlikely. Even before the introduction of automated trawling of fingerprint databases in the 1970s, fingerprint analysts tediously compared latent prints to the databases. Systems for organizing fingerprints by features such as arches, whorls, and loops on each finger assisted in these searches. Automation, however, "made crime scene processing dramatically more productive. Local and county AFIS purchases were usually justified on the basis of their crime-solving potential." (Moses 2011, p. 6-9). Latent-print searches were not "routine" in the sense that most cases did not lend themselves to this investigative technique, but "fingerprints for random crime-solving" predates electronic searching. One forensic science textbook refers to San Francisco’s hit rate "of 8 percent for manual latent print searches." (Saferstein 2d 2004, p. 416).

Electronic searching, however, made trawls of arrestee databases more feasible, successful, and, yes, systematic. In San Francisco, in 1983, "a new crime scene unit was organized specifically with the new [AFIS] system as its centerpiece. ... All latents that met minimum criteria [were] searched in AFIS." Id. at 6-7. The result was "a dramatic 10-fold increase in latent print identifications in 1984." Id. at 6-8. As with DNA today, database hits made international news. (E.g., id. at 6-8; Elmer-Dewitt 1985). Today, they are less publicized, but no less real. (See Kaye 2013, p. 38 n. 38 (collecting statistics indicating that hundreds of thousands of fingerprint database trawls occur annually in active and cold cases combined)).

In short, claims that "[l]atent prints” recovered from crime scenes are not systematically compared against the database of known fingerprints," 133 S. Ct. at 1987 (Scalia, J., dissenting), and that "[p]olice have never routinely collected or used ... prints for random crime-solving purposes" (Murphy 2013, p. 166), understate a common use of fingerprint databases. The most that can--and should--be said is that, historically, the primary motivation for amassing large arrestee fingerprint databases was not to trawl them for matches to latent prints from crime scenes. It was to ascertain whether an arrestee's prints already were in the database as a result of a previous arrest.

To that extent, arrestee DNA profiling differs from arrestee fingerprinting. DNA profiling always had criminal-intelligence gathering as its primary purpose. Although today that also is a major purpose of arrestee fingerprinting, it was not always so. This historical fact returns us a crucial question: Given that both types of biometric data now have the same two uses in the criminal justice system, and given the differences between fingerprints and DNA samples (as opposed to profiles), should the law treat them differently? The dissenting opinion offers no convincing answer.3/

Notes
  1. Justice Scalia is one of least likely Justices to accept Professor Murphy's theory that the mere "analysis of genetic code" is, as she has suggested elsewhere, a "constitutional moment" separate from the acquisition of the sample. Erin Murphy, Relative Doubt: Familial Searches of DNA Databases, 109 Mich. L. Rev. 291, 334 (2010). In King, Justice Scalia did not state or imply that "analysis of genetic code" is a search in itself, and his remarks at oral argument suggest that it is the physical aspect of DNA acquisition--the trespass on the person--that was dispositive for him. Cf. Ferguson v. City of Charleston, 532 U.S. 67, 92 (2001) (Scalia, J., dissenting and maintaining that “only one act ... could conceivably be regarded as a search ... the taking of the urine sample”) (cited in Murphy, supra).
  2. If the dissent's critique of the analogy to fingerprinting is simply that fingerprinting is less invasive than buccal swabbing, then the collection method in the text eliminates the argument. If the dissenting Justices believe what Professor Murphy implies--that the "analysis of genetic code" is itself a Fourth Amendment "search"--then they are trodding new ground without the benefit of any argument or analysis.
  3. The majority opinion reaches its conclusion rather summarily as well.
References
  • Brief for the States as Amici Curiae Supporting Petitioner, Maryland v. King, No. 12-302, Jan. 2, 2013.
  • Cal. Dep’t of Just., Office of the Attorney General, BFS DNA Frequently Asked Questions: Effects of the All Adult Arrestee Provision, http://oag.ca.gov/bfs/prop69/faqs, last accessed Nov. 27, 2013.
  • Paul Dawson et al., Residence Time and Food Contact Time Effects on Transfer of Salmonella Typhimurium from Tile, Wood and Carpet: Testing the Five-second Rule, 102 J. Applied Microbiology 945 (2007).
  • Philip Elmer-Dewitt, Computers: Taking a Byte Out of Crime, Police Hail Computer System that Cracked the Night Stalker Case, Time Mag., Oct. 14, 1985, available at http://content.time.com/time/magazine/article/0,9171,960128,00.html.
  • David H. Kaye, Maryland v. King: Per Se Unreasonableness, the Golden Rule, and the Future of DNA Databases, 127 Harv. L. Rev. Forum 39 (2013), available at http://ssrn.com/abstract=2340456.
  • Kenneth R. Moses, Automated Fingerprint Identification System (AFIS),in The Fingerprint Sourcebook ch. 6 (Alan McRoberts & Debbie McRoberts eds., 2011), available at http://www.ncjrs.gov/pdffiles1/nij/225326.pdf.
  • Erin Murphy, License, Registration, Cheek Swab: DNA Testing and the Divided Court, 127 Harv. L. Rev. 161 (2013).
  • Richard Saferstein, Criminalistics: An Introduction to Forensic Science (8th ed. 2004).
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Wednesday, 27 November 2013

Maryland v. King: When Being Smart and Witty Isn't Enough

Justice Scalia's dissenting opinion in Maryland v. King, the arrestee-DNA case, has been praised as "one of the best Fourth Amendments dissents, ever" and his "smartest, wittiest ruling of all time." [1] But one man's wit is another's vitriol, and the opinion, according to another law professor, is "dripping with contempt." [2]  Stylistically, this opinion is more evidence that the art of writing with courtesy as well as conviction has been lost.

Substantively, what makes this dissent "one of the best"--other than one's feelings about which result is correct? It cannot be that the opinion sets forth some enduring principle for understanding and applying the Fourth Amendment. The opinion is less concerned with what the Maryland police did than with why they did it. Thus, the opinion begins with the following seemingly bright-line rule: "[w]henever this Court has allowed a suspicionless search, it has insisted upon a justifying motive apart from the investigation of crime" and then single-mindedly devotes itself to demonstrating that the "primary purpose [of the search] was to detect evidence of ordinary criminal wrongdoing." Id. at 1981-82. In the process, it overlooks the real possibility that something about the type of search and evidence in question makes the putative rule inapposite.

I say "putative rule" because the law is not as clear as the opinion suggests. The Court allowed a suspicionless search of a person on parole in Samson v. California, 547 U.S. 843 (2006). Although the majority led by Justice Kennedy in King relied prominently on Samson, Justice Scalia made no effort to disavow or distinguish the case.

More fundamentally, the dissent's desire for a rule that prohibits all suspicionless searches that have as their "primary purpose" the production of evidence of a crime leads to an odd result. The police may not collect a DNA sample by painlessly swabbing the inside of a cheek if they intend to see whether it matches one on file from an unsolved murder, rape, or other crime; however, they can if they want the same DNA profile, first and foremost, to verify the name and look up any previously recorded criminal history of the same person. Other than reciting the supposedly absolute rule about motives, the dissent offers no justification for this difference. It does not contest the majority's claim that the nature of the invasion of personal security and privacy in King is minor, akin to photographing or fingerprinting an arrested person. (I will look at what the dissent had to say about photography and fingerprinting in a separate posting.)

In criminal procedure cases, Justice Scalia favors absolute rules that require little inquiry into competing values. In King, this mode of analysis allowed him to vehemently insist that the Fourth Amendment does not allow forcing a prisoner to provide a small DNA sample. Yet, he did not dissent from Justice Kennedy's opinion in Florence v. Chosen Board of Freeholders, 132 S. Ct. 1510 (2012), which upheld a police practice of forcing all prisoners in jails to disrobe, open their mouths, wiggle their tongues, and move their genitalia so that their jailers could inspect their nude bodies--all without the slightest suspicion that the individual is concealing evidence or contraband. [3] In that case, why did Justice Scalia express no doubt that "the proud men who wrote the charter of our liberties would have been so eager to open their mouths for royal inspection"? King, 133 S.Ct. 1958, 1989 (2013) (Scalia, J., dissenting).

To avoid misunderstanding, I hasten to add that I too find the dissenting opinion powerful, at least when it comes to showing that Maryland's primary legislative purpose in authorizing DNA collection and analysis before conviction was to investigate crimes other than ones for which the arrest is made. But that was hardly a blinding insight [4], and the opinion does not address the more basic question of why the intent to gather evidence should invalidate biometric data collection. Is it unconstitutional for police to collect fingerprints from arrestees with the sole intent to check them against a database of latent prints from unsolved crimes? With the database check as the "primary purpose"? Id. at 1981-82 emphasis added). It is nearly impossible to tell from this, Justice Scalia's "smartest ... ruling."

References
  1. Jeffrey Rosen, A Damning Dissent: Scalia's Smartest, Wittiest Ruling of All Time, New Republic, June 4, 2013, available at http://www.newrepublic.com/article/113375/supreme-court-dna-case-antonin-scalias-dissent-ages.
  2. Noah Feldman, Grumpy Old Scalia v. Those Pesky Kids, Bloomberg View, June 30, 2013, http://www.bloomberg.com/news/2013-06-30/grumpy-old-scalia-v-those-pesky-kids.html.
  3. Sherry F. Colb, The Road to Justice Scalia Is Paved With (Some) Intentions, Verdict, June 12, 2013, http://verdict.justia.com/2013/06/12/the-road-to-justice-scalia-is-paved-with-some-intentions#sthash.v1VilcDr.dpuf
  4. David H. Kaye, Who Needs Special Needs? On the Constitutionality of Collecting DNA and Other Biometric Data from Arrestees, 34 J. L., Med. & Ethics 188 (2006), available at http://ssrn.com/abstract=944359
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Wednesday, 20 November 2013

The Significance of Significance

Today’s issue of Nature includes a cautionary essay entitled “Twenty Tips for Interpreting Scientific Claims.”  The essay is written by two conservation biologists (William J. Sutherland and Mark Burgman) and one statistician (David Spiegelhalter)—all eminent in their fields. The essay lists “20 concepts that should be part of the education of civil servants, politicians, policy advisers and journalists—and anyone else who may have to interact with science or scientists.”

Increasing statistical and scientific literacy is a laudable goal, but it is not at all easy to achieve. The late David Freedman and I struggled to describe some 16 of the 20 concepts for judges in a reference manual for judges. By and large, our expositions are consistent with the short ones in Twenty Tips, but two tips seem less useful than others.

First, how many policy makers, journalists, or other consumers of scientific information need to be told that smaller samples tend to be less representative (assuming that everything else is the same)?    Twenty Tips seems to suggest that sample size usually should be on the order of "tens of thousands":
Bigger is usually better for sample size. The average taken from a large number of observations will usually be more informative than the average taken from a smaller number of observations. That is, as we accumulate evidence, our knowledge improves. This is especially important when studies are clouded by substantial amounts of natural variation and measurement error. Thus, the effectiveness of a drug treatment will vary naturally between subjects. Its average efficacy can be more reliably and accurately estimated from a trial with tens of thousands of participants than from one with hundreds.
Nobody can dispute the truth of the bolded heading if “better” means more likely to produce an estimate of a population parameter that is close to its true value. The problem I have seen with judges, however, is not that they do not appreciate that large samples usually are preferable to small ones when accuracy is the only criterion of what is “better.”  It is that they are overly impressed with the perceived need for very large samples when smaller ones would be quite satisfactory. They do not recognize that doubling the sample size rarely doubles the precision of an estimate. They think a fixed percentage of large population needs to be sampled to obtain a good estimate.

Although this reaction merely concerns the understandable incompleteness of a short tip, the second tip I will mention contains more of an invitation to misunderstanding or misinterpretation. According to Twenty Tips
Significance is significant. Expressed as P, statistical significance is a measure of how likely a result is to occur by chance. Thus P = 0.01 means there is a 1-in-100 probability that what looks like an effect of the treatment could have occurred randomly, and in truth there was no effect at all. Typically, scientists report results as significant when the P-value of the test is less than 0.05 (1 in 20).
The explanation of this call for “significant" results invites confusion. First “statistical significance” is not “expressed as P.” Rather a P-value is (arbitrarily) translated into a yes-no statement of “significance.” Second, “P = 0.01” does not mean “there is a 1-in-100 probability that . . . in truth there was no effect at all.” It means that if “in truth there was no effect at all,” differences denominated “significant” at the 0.01 level would be seen about 1 time in 100 in a large number of repeated experiments.

I am being picky, but that comes from being a lawyer who worries about the choice of words. The paragraph on the significance of significance certainly could be read more charitably, but I suspect that the policy-makers it is intended to educate easily could misunderstand it. Indeed, judicial opinions are replete with transpositions of the P-value into posterior probabilities, and Twenty Tips offers little immunity against this common mistake.

References

David H. Kaye & David A. Freedman, Reference Guide on Statistics, in Reference Manual on Scientific Evidence, National Academy Press, 3d ed., 2011, pp. 211-302; Federal Judicial Center, 2d ed., 2000, pp. 83-178; Federal Judicial Center, 1st ed., 1994, pp. 331-414

William J. Sutherland, David Spiegelhalter & Mark Burgman, Policy: Twenty Tips for Interpreting Scientific Claims, Nature, Nov. 20, 2013, http://www.nature.com/news/policy-twenty-tips-for-interpreting-scientific-claims-1.14183?WT.ec_id=NATURE-20131121
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Monday, 19 August 2013

Ninth Circuit Upholds Indefinite Retention of DNA Samples: But Why Retain Them?

Having considered the legal basis and justifications for allowing convicted offenders to demand that the DNA samples taken from them be removed from the FBI's repository [1, 2, 3], we should look on the other side of the coin. How strong are the justifications for retaining the DNA samples in the first place?

According to the Kriesel III majority, the "primary justification" for keeping samples is that "match confirmation" ensures "the continued accuracy and integrity of the CODIS system." That is:
Upon receiving a CODIS Match Report, the ... FDDU [Federal DNA Database Unit] locates the retained blood sample ... , re-extracts junk DNA from it, and runs a new analysis. If the newly generated profile is the same as the one in CODIS that formed a Candidate Match, the match is confirmed and the accuracy of the match between the CODIS profile and the identified offender is ensured. The confirmation of the CODIS match is thus achieved by comparing the profile generated from the retained sample with the Codis profile. Although CODIS has not yet encountered such a “mismatch” or “misidentification” error, in the event that the generated profile did not match the CODIS profile, the lab would then determine what caused the error and, presumably, prevent similar errors from occurring in the future.
Let's pause to note the infelicities here. First, a cavil about phrasing. The government does not just extract "junk DNA" (a term that is best avoided). It extracts the entirety of the physical genome (all the DNA) but types only a small number of loci that do not reveal much about the individual's health or fitness. Second, a match to the DNA sample that is on file (as a spot on a card) does not "ensure" that the "identified offender" matches the crime-scene sample. If the name associated with the card is incorrect (Mr. Jones's DNA has been recorded as Mr. Smith's), the profile is not the offender's even though both DNA profiles match. [4]

Still, the retyping step does protect against recording a profile in the database that is not the one on the card; moreover, as Judge Schroeder observed, "[i]t also enables pre-arrest confirmation of a match."

The dissent's response is that
The government's argument is severely undercut by the fact that the CODIS database has never led to a false identification of a suspect ... . Moreover, if by some remote chance, there was an unprecedented error in the CODIS system, that error would be swiftly discovered when the CODIS-identified suspect had a new blood sample drawn and the new sample was compared with the DNA found at the crime scene, as is the regular practice. For this reason alone, the government's rationale is wholly theoretical at best and, to put it bluntly, is entirely without merit.
Entirely without merit? Surely a DNA database can create an ordeal for a suspect who is arrested even if later testing of an entirely new sample from him leads to his release. [5] Judge Reinhardt seems to maintain that a mistyped DNA sample or a misrecorded profile could not "infringe the liberty of the misidentified suspect" because it merely "pertains to not taking a blood sample from the wrong person as a result of a CODIS misidentification." But police do not simply ask suspects who come to their attention because of a database hit to mail in a DNA sample at their convenience. Often, they arrest these suspects. Although the jailed suspects may have a get-out-jail-free card in the form of their DNA, it can take time to play it. [6]

The stronger argument is that the indignity and injury that comes from being an active suspect in a criminal investigation and, quite possibly, being detained and interrogated is, as the dissent ultimately recognizes, "an unfortunate occurrence, but avoiding this wholly theoretical and comparatively minor infringement on the suspect's rights cannot, by any measure, justify the retention of the entirety of that individual's, and millions of others', private genetic information for the rest of their lives."

But even this formulation is misconceived. The pertinent balance is either (1) between a single individual's risk of being falsely arrested as opposed to the same individual's risk of having truly private areas of his genome examined by the government, or (2) between these same risks summed over everyone in the database. To balance between a single individual's risk of being falsely identified and everyone's risk of improper acquisition or disclosure of genetic data is to place a very heavy thumb on the scales.

The dissent also dismisses the government's argument that avoiding public disclosure of laboratory or clerical errors is a good reason to hang on to samples. This point is well taken. Why should the government fear that the public might discover the obvious--that some mistakes are possible when an organization maintains millions of records? CODIS's efficacy (and public confidence in it) would not suffer if preliminary false matches are rare and inevitably corrected by confirmatory testing of fresh samples, as the government claims.

Finally, the dissent suggests that the FBI's "quality assurance" strategy of "randomly re-testing 1% of samples that were received by the FBI laboratory in the previous six months" cannot justify retaining millions of samples for more than six months. Certainly, less drastic methods of quality assurance are available. For example, the FBI could keep only 1% of the samples for re-testing. But this procedure would make it more difficult to correct a large number of profiles if they turned out to be incorrect. Suppose that a discrepancy resulted from a problem that affected all the samples placed on a tray with many wells on a given day. (This may not be the current technology, but it illustrates the broader point.) It might be easier to retrieve these samples from storage and retype them than to locate and collect more DNA from the individuals who provided the affected samples. However, if errors are as improbable as the dissent maintains, this precaution would not be justified.

Interestingly, one traditional argument for sample retention is absent from both opinions (apparently because the government did not raise it). What if some of the old loci are retired and new ones are used as replacements? (Maybe the former will be found to have privacy-laden associations with phenotypes?) Sample retention obviates any possible need to obtain new samples--a task that could prove quite onerous given the size of modern databases. Then too, what if outer-directed database trawling [7] is undertaken? A recent report proposes that "familial searching" as implemented in California could classify crime-scene samples from not-so-close relatives as coming from first-degree ones, causing turmoil for the first-degree relatives and complicating matters for the police. [8] One solution (if this is a real problem) would be to analyze more loci in the samples to ascertain the relationship with greater confidence. [9, 10]

In sum, Judge Reinhardt's complaint that "tens if not hundreds of millions of dollars expended on maintaining a totally unnecessary and wholly pointless system of collecting and maintaining tens of millions of blood samples indefinitely in a national warehouse" seems overdrawn--but the justifications discussed in the Kriesel III opinions for indefinite and widespread sample retention also seem strained. The value--immediate and potential--of sample retention is more complex than the case suggests, but it is unlikely that the government would suffer greatly if it had to destroy samples from individuals like Kriesel, who have completed their sentences. Indeed, however one comes out on the issue of the individual's Fourth Amendment right to compel eventual destruction or disgorgement of databank samples, even initial sample retention may not be the best public policy. [11]

References

1. Ninth Circuit Upholds Indefinite Retention of DNA Samples: The Majority Opinion in Kriesel III, July 17, 2013, http://for-sci-law-now.blogspot.com/2013/07/ninth-circuit-upholds-indefinite.html

2. Ninth Circuit Upholds Indefinite Retention of DNA Samples: The Dissent’s Perception of the Loss of Privacy in Kriesel III, July 18, 2013, http://for-sci-law-now.blogspot.com/2013/07/ninth-circuit-upholds-indefinite_18.html

3. Ninth Circuit Upholds Indefinite Retention of DNA Samples: More Problems with Judge Reinhardt’s Dissenting Opinion, July 25, 2013
http://for-sci-law-now.blogspot.com/2013/07/ninth-circuit-upholds-indefinite_25.html

4. Police Finger Wrong Man after DNA Data Mix-up, Asahi Shimbun, Mar. 22, 2010, http://www.asahi.com/english/TKY201003210142.html

5. Linda Geddes, DNA Super-network Increases Risk of Mix-ups, New Scientist, Sept. 5, 2011, http://www.newscientist.com/article/mg21128285.500-dna-supernetwork-increases-risk-of-mixups.html#.UhJ-zH-wXdU

6. Jack Doyle, Innocent Man Spent Five Months in Prison After Forensics Mix-up Meant He Was Falsely Accused of Rape, Daily Mail, Oct. 1, 2012, http://www.dailymail.co.uk/news/article-2211365/Adam-Scott-Innocent-man-spent-FIVE-MONTHS-prison-forensics-mix-meant-falsely-accused-rape.html#ixzz2cSKkGvBI


7. David H. Kaye, The Genealogy Detectives: A Constitutional Analysis of “Familial Searching”, 51 Am. Crim. L. Rev. 109 (2013), available at http://ssrn.com/abstract=2043091

8. Rori V. Rohlfs, Erin Murphy, Yun S. Song, Montgomery Slatkin, The Influence of Relatives on the Efficiency and Error Rate of Familial Searching, 8 PLoS ONE e70495, http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0070495

9. Jianye Ge et al., Haplotype Block: A New Type of Forensic DNA Markers, 6 Forensic Sci. Int’l Genetics 322 (2011)

10. Chad Huff et al., Maximum-likelihood Estimation of Recent Shared Ancestry (ERSA), 21 Genome Research 768 (2011)

11. David H. Kaye, Behavioral Genetics Research and Criminal DNA Databanks, 69 Law & Contemporary Problems 259 (2006), available at http://ssrn.com/abstract=1411861
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Tuesday, 30 July 2013

More on the Population-wide Database

Chris Halikes, posted a comment on yesterday's blog posting about expanding the DNA database to the entire population. He expressed the following concern:
The mathematics of coincidental matches, particularly with respect to the size of the database, is a thorny subject. However, the odds of a coincidental match seem to rise (the so-called birthday problem). Given the strength of the tunnel vision that sets in when DNA is involved (the Lukis Anderson/Raveesh Kumra case is a recent example), I would think long and hard about the wisdom of having an all-inclusive database.
The prospect of more false accusations definitely deserves thought.

In evaluating this risk, the birthday problem is not on point. In the birthday problem, the number of comparisons grows exponentially with the number of people of in the room because there is no single birthday of interest. For a group of size N, there are approximately N2/2 comparisons. For a fixed birthday, however, there are only N comparisons. 

In case work, no one examines all possible pairs of profiles. Like a fixed birthday, a single crime-scene profile is compared to the profiles in the database. Because the number of comparisons is N, the risk grows only linearly with the size of the database. The exponential growth in the Birthday Paradox does not occur.

CODIS is expanding the number of loci in the profile, so the chance that two people (other than monozygotic twins) share the same profile will be even smaller than it is now. When the crime-scene sample yields a good profile (say, 16 or more loci), I cannot see why increasing the database size to that of the entire population would produce many matches to people whose DNA was not at the crime-scene.

The record of an innocent monozygotic twin would pop up in every database trawl for a crime-scene DNA profile that actually belongs to the guilty twin. Strictly speaking, these are not these "coincidental," because there is a deterministic explanation. For such matches -- and for truly coincidental ones -- the population-wide database flags the problem for the police. They get matches to more than one individual! They will know that they must investigate further. Thus, universality alleviates the problem of a "coincidental match" by making every such match apparent.

The problem in the Kumra case, according to prosecutors, was secondary transfer to fingernails that (I assume) did not have DNA from the actual killers. Likewise, if the police or anyone else plants DNA from a target in an incriminating place where the perpetrator's DNA might be found -- and the perpetrator's DNA is not there -- the database trawl will identify the target instead of the perpetrator.

If a crime-scene sample becomes contaminated with extraneous DNA from individuals who were not present at the crime-scene  in an amount sufficient to yield a clear and complete profile, the result could be a false accusation and ensuing conviction for people living in the vicinity, being in the correct age range and physical capacity, and lacking a convincing alibi.

Another limitation of DNA databases is that, at best, they can only show that an individual was at a crime-scene at some point. If police and prosecutors unreflectively equate presence with guilt and a suspect has no persuasive explanation for his presence, injustice could follow. However, this is a problem today. Arguably, a universal database might diminish the problem: cases of innocent presence would arise more often, leading to greater sensitivity to this limitation.

Less worrisome are errors such as mislabeling or mistyping the samples in the database. If the profile recorded for me is not my profile but was present at the crime-scene, this mistake will become apparent when I am retested after the cold hit, as is standard procedure. The confirmatory test will exclude me.

A population-wide has other advantages than those I mentioned today and yesterday -- but it also has its share of disadvantages.

References

Related Postings

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Monday, 29 July 2013

On the Hypothetical Population-wide DNA Database

The August ABA Journal landed in my mailbox. Usually, I ask reporters to check with me on the wording before quoting. Alas, I neglected to do so some weeks ago, when Mark Walsh asked me about DNA databases in the aftermath of the Supreme Court's opinion in Maryland v. King. Mr. Walsh's article quotes me as follows: "Is the point of arrest the sensible place to draw the line? I can imagine a system in which you take a sample from everyone. Newborns already have a heel prick taken for certain genetic testing. At the same time you could take a DNA sample. Not that you expect a newborn to commit a crime, but 20 years later the sample is there in the database."

Oops! I said that? I meant to say this: "Is the point of arrest the sensible place to draw the line? I can imagine a system in which you take a sample from everyone. Newborns already have a heel prick taken for certain genetic testing. Along with these genetic tests, you could obtain a DNA profile. Not that you expect a newborn to commit a crime, but 20 years later the profile is there in the database." The critical difference: "profile," not "sample."

Here is the way that Michael Smith, Ed Imwinkelried and I explained the idea (which was stimulated by remarks of Phil Reilly to the legal issues working group of the National Commission on the Future of DNA Evidence) in another ABA publication back in 2001:
Creating a national identification database all at once would be prohibitively expensive today, even if we had the laboratory capacity to do it. But DNA typing technology is advancing at a pace reminiscent of the exponential growth in computer microprocessing power that has made the “personal computer” a fixture on every desk. Soon it will be feasible to create a DNA identification record for everyone, at least prospectively. For example, it would be easy to extract identification profiles as an adjunct to the existing public health programs that for many years have screened DNA samples from almost all newborns, to identify infants with treatable genetic diseases. The identification profiles could be transmitted to a single, secure, national database. The genetic locations (“loci” is the technical term) used for those identification profiles would be strictly limited to sequences that have no implications for health or other significant physical or mental traits. Furthermore, access to the database would be limited to law enforcement personnel investigating specific crimes in which DNA trace evidence already has been found. Law enforcement agencies would not need—and should not be permitted—to handle, much less retain, the samples.

... Not only would a comprehensive database be valuable to the criminal justice system, but it also would be useful in identifying remains after natural disasters, mass accidents, and terrorist attacks. Such a database is, we  believe, socially advantageous. But we would be the first to acknowledge that this belief is surely debatable, and a panoply of questions must be considered.
...
In the database system we envision, the information that the government is allowed to have is very different from the types that have sparked debates over medical privacy. The preponderance of the human genome consists of sequences that have no medical importance or social significance. Much of the genome is “noncoding” — these sequences are not translated into the proteins that are the machinery of cells — and most of them are not genetically “linked” to any coding sequences. Even in the coding regions, many DNA sequences merely code for traits such as gross features of fingerprints or the pattern of hair follicles in the skin that have no stigmatizing potential. Consistent with current practice, we would limit the database loci to such regions. Consequently, the genetic information included in the database would be no more invasive of privacy than an image of the ridges and whorls in a fingerprint or of the blood vessels in the retina of the eye.
...
[T]he system we envision keeps almost all samples out of the hands of law enforcement officials. Recall that the initial typing would be done by health workers, not police, as part of neonatal screening. No samples would be sent to law enforcement agencies — they would receive only the biometric genotypes that have no use except for identification. To the extent that additional sampling, say, of immigrants or citizens born abroad, would be necessary to cover as much of the population as possible, the sample could be destroyed as soon as the typing is complete. In fact, an instrument could be built that would extract an identifying profile and destroy the sample at the same time. Proper procedures for sampling the DNA, extracting the identifying profile, and immediately destroying the sample would protect everyone’s genetic privacy — to the extent we have any when private hospitals and HMOs keep samples of our blood and other tissue together with information far more sensitive than the random bits of DNA that identify us. The government officials maintaining the database could neither invade privacy nor enable insurers or employers to do so.
Looking back at these words 12 years later, I would change some of them as well. That the identification loci are not protein-coding is not sufficient to prove that they have no clinical predictive or diagnostic value. Moreover, the loci certainly are more informative than fingerprints or retinal patterns with respect to ascertaining parentage or siblingship. A population-wide database of profiles with the current CODIS loci would make it possible for the government to do "legitimacy testing" -- that is, to check families for children born out of wedlock. Other privacy questions would need to be addressed as well. As we wrote in 2001, "Our vision is futuristic ... incomplete and tentative. Many details remain to be worked out."

References

  • David H. Kaye, Michael E. Smith, and Edward J. Imwinkelried, Is a DNA Identification Database in Your Future?, Criminal Justice, Fall 2001, at 5-9, 19
  • Mark Walsh, "21st Century Fingerprinting," ABAJ, Aug. 2013, at 16-17

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Saturday, 27 July 2013

Contamination or Sasquatch in Forensic Laboratories -- Which Is it?

DNA Diagnostics, Inc., is “a laboratory that provides multi-species testing including human as well as animal DNA testing for individuals, law enforcement, breed associations, and state regulatory agencies.”The lab
  • “participates in both human and animal proficiency testing”
  • has staff who are “eminently qualified to provide superior DNA testing services” and of “unquestionable quality,” and
  • performs “testing ... of the highest quality” (including “high volume genetic testing”) with “state of the art instrumentation and modern facilities .. on the cutting edge of technology in DNA testing.
Thus, “[s]taff members ... have been accepted in court as experts in human and animal forensic DNA testing ... for the prosecution and the defense and in [state and federal] criminal and civil cases.”

These attributes are what one would want in a forensic laboratory, and the work of this laboratory is nothing short of amazing. Last November, it issued a press release that “calls on public officials and law enforcement to immediately recognize the Sasquatch as an indigenous people.”

The Sasquatch? As in Bigfoot?

Absolutely. A “team of experts in genetics, forensics, imaging and pathology, led by Dr. Melba S. Ketchum ... sequenced 3 complete Sasquatch nuclear genomes and determined the species is a human hybrid” living in North America. The team discovered that “the legendary Sasquatch is a human relative that arose approximately 15,000 years ago as a hybrid cross of modern Homo sapiens with an unknown primate species.” Mitochondrial and “next generation sequencing [of] 3 whole nuclear genomes ... indicate that the North American Sasquatch is a hybrid species, the result of males of an unknown hominin species crossing with female Homo sapiens.”

This might seem amusing, but the study director’s responses to other scientists who interpret the results, not as proof of a hybrid species, but as an indication of contaminated samples, sound eerily like what one hears in court. John Timmer, a science writer and molecular biologist, describes what he found when he examined the “genomes” and conferred with her:
In cases where the hair comes attached to its follicle, it's possible to extract DNA from its cells. And that is exactly what the bigfoot team did, using a standard forensic procedure that was meant to remove any other DNA that the hair had picked up in the interim. If everything worked as expected, the only DNA present should be from whatever organism the fur originated from.

And, in Ketchum's view, that's exactly what happened. They worked according to procedure, isolating DNA from the hair follicles and taking precautions to rule out contamination by DNA from anyone that was involved in the work. Because of this, Ketchum is confident that any DNA that came from the samples once belonged to whatever creature deposited the fur in the woods—no matter how confusing the results it produced were. "The mito [mitochondrial DNA results] should have done it," she argued. "It's non-human hair—it's clearly non-human hair—it was washed and prepared forensically, and it gave a human mitochondrial DNA result. That just doesn't happen."

Ketchum was completely adamant that contamination wasn't a possibility. "We had two different forensics labs extract these samples, and they all turned out non-contaminated, because forensics scientists are experts in contamination. We see it regularly, we know how to deal with mixtures, whether it's a mixture or a contaminated sample, and we certainly know how to find it. And these samples were clean."
Timmer’s article on how science went wrong is well worth reading — and chilling if you think about how DNA Diagnostics’ director -- an eminently qualified expert witness -- might testify about contamination in a more mundane case.

References

Acknowledgment: Thanks to Joe Cecil for calling John Timmer's article to my attention.
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