Maryland v. King No. 3: Bertillonage as Precedent

There are lots of criticisms that one can make of the majority opinion in Maryland v. King -- and even more that apply to the dissent -- but, contrary to one commentator, I do not think that the Court's reference to the use of anthropometrics as employed in the late 1800s and early 1900s for authenticating the identities of prisoners is particularly problematic. The Court wrote:

Beginning in 1887, some police adopted more exacting means to identify arrestees, using the system of precise physical measurements pioneered by the French anthro­pologist Alphonse Bertillon. Bertillon identification con­sisted of 10 measurements of the arrestee’s body, along with a “scientific analysis of the features of the face and an exact anatomical localization of the various scars, marks, &c., of the body.” Defense of the Bertillon System, N.Y. Times, Jan. 20, 1896, p. 3. “[W]hen a prisoner was brought in, his photograph was taken according to the Bertillon system, and his body measurements were then made. The measurements were made . . . and noted down on the back of a card or a blotter, and the photograph of the prisoner was expected to be placed on the card. This card, therefore, furnished both the likeness and description of the prisoner, and was placed in the rogues’ gallery, and copies were sent to various cities where similar records were kept.” People ex rel. Jones v. Diehl, 53 App. Div. 645, 646, 65 N. Y. S. 801, 802 (1900). As in the present case, the point of taking this information about each ar­restee was not limited to verifying that the proper name was on the indictment. These procedures were used to “facilitate the recapture of escaped prisoners,” to aid “the investigation of their past records and personal history,” and “to preserve the means of identification for . . . future supervision after discharge.” Hodgeman v. Olsen, 86 Wash. 615, 619, 150 P. 1122, 1124 (1915); see also McGovern v. Van Riper, 137 N. J. Eq. 24, 33–34, 43 A. 2d 514, 519 (Ch. 1945) (“[C]riminal identification is said to have two main purposes: (1) The identification of the accused as the person who committed the crime for which he is being held; and, (2) the identification of the accused as the same person who has been previously charged with, or convicted of, other offenses against the criminal law”).

After Jake Sherkow, a Fellow at Stanford's Center for the Law and Biosciences, suggested that this recounting of legal history was an "appeal to the truly ugly portion of nineteenth century criminology" and that Bertillonage was "proto-eugenics," he and I corresponded about the value of these measurements for biometric authentication and their putative connection to the eugenics movement. We pretty much converged in our understanding of these matters (see http://blogs.law.stanford.edu/lawandbiosciences/2013/06/11/maryland-v-king-corrections-department-david-kaye-on-bertillonage/), but I think we still disagree on the wisdom of the Court's including a reference to the legal history in its opinion.

I would agree that Justice Kennedy could have made the same point solely with early opinions on the propriety of fingerprinting. However, anthropometrics and photography contributed mightily to that line of cases. The justice began his discussion of fingerprinting with United States v. Kelly, 55 F. 2d 67 (2d Cir. 1932), presenting it as "the seminal case." In fact, it was a part of a long series of cases. E.g., Downs v. Swann, 73 A. 653 (Md. 1909); David H. Kaye, A Fourth Amendment Theory for Arrestee DNA and Other Biometric Databases, 15 U. Pa. J. Const. L. 1095, 1098 n.9 (2013); http://for-sci-law-now.blogspot.com/2012/12/the-judicial-reception-of-acquiring.html. But see with Wayne A. Logan, Policing Identity, 92 B.U. L. Rev. 1561, 1580 (2012) (arguing that Kelly represented a major shift in the caselaw)..

Ignoring judicial approval of anthropometrics and photography therefore would have been ahistorical, especially considering that cases such as Downs saw fingerprints as part of a combined system -- in modern jargon, a multibiometric authentication system. And that is what DNA and fingerprints are today.

Of course, it is not all they are. Both fingerprints and DNA also serve the police intelligence function of associating individuals to crime scenes. The dissenting four justices believe that it is unconstitutional to take arrestee DNA to use it in this manner. I shall consider their reasoning and rhetoric later.

Maryland v. King: Interlude

The more I ruminate on the opinions in Maryland v. King, the more I find the dissenting opinion irritating and the majority opinion disappointing. But explaining precisely why is not so easy. Meanwhile, I can recommend the following early but penetrating comments on the opinions:

• Hank Greely, Maryland v. King - The Coming California Sequels, Law and Biosciences Blog, June 8, 2013
• ----- , The Supreme Court Decision in Maryland v. King, Law and Biosciences Blog, June 3, 2013
• Richard Lempert, Maryland v. King: An Unfortunate Supreme Court Decision on the Collection of DNA Samples, Brookings Up Front, June 6, 2013
  

Update: see also

• Sherry F. Colb, The Road to Justice Scalia Is Paved With (Some) Intentions: The Supreme Court Decides Maryland v. King, Verdict, June 12, 2013

Maryland v. King No. 2: Was There a Search?

In anticipation of the Supreme Court’s review of Maryland v. King, I proposed that a suitable opinion on routine pre-conviction DNA collection would require the Court to

evaluate the actual interests implicated by preconviction searches, properly defined; articulate the appropriate framework for evaluating the reasonableness of warrantless searches in general; and attend to the complexities in applying that framework to the biology of DNA identification tests and to the limited information recorded in DNA databases.  An opinion that accomplishes these tasks should supply not only a truly “considered analysis” of the constitutionality of DNA-BC but also much needed guidance on the limits of totality balancing in all Fourth Amendment cases.

David H. Kaye, On the “Considered Analysis” of DNA Collection Before Conviction, 60 UCLA L. Rev. Disc. 104 (2013).

The Court now has spoken. Justice Kennedy, joined by the Chief Justice and Justices Thomas, Breyer, and Alito, wrote an opinion upholding Maryland’s law as constitutionally reasonable. Their opinion lists—with approval—all the colorable reasons a state could have for enacting such a law. Justices Scalia, joined by Justices Ginsberg, Kagan, and Sotomayor, correctly but scathingly responded that the Maryland legislature was not really pursuing all these goals in enacting and implementing its law.

From the standpoint of developing more coherent Fourth Amendment doctrine, both opinions have major limitations. The majority opinion, I shall argue, does little to provide the much needed guidance as to when totality balancing applies. The dissenting opinion, on the other hand, adopts a clearer rule but ignores the reasons for the rule (beyond a contested reading of the history of the Fourth Amendment).

The threshold question in King, as in any Fourth Amendment case, is whether a search occurred. The issue was not really in dispute. As the majority opinion points out, cases decided under the “reasonable expectation of privacy” rubric of Katz v. United States had held that requiring an individual to expel air from deep within his lungs, to submit to a blood draw, and to have debris gently scrapped from beneath a fingernail all have been deemed searches. Scraping the inside of the cheek falls in the same category. See also David H. Kaye, The Constitutionality of DNA Sampling on Arrest, 10 Cornell J. L. & Pub. Pol'y 455 (2001).

More recently, the Court has been applying an analysis more closely related to the common law of trespass to decide whether particular information-gathering practices are searches. In United States v. Jones, a majority held that affixing an object—a GPS transmitter—to personal property—a car—was a search even if did not invade a reasonable expectation of privacy. In Florida v. Jardines, a different majority held that bringing a drug-detecting dog onto the porch of a house to sniff was a search on the basis of a similar trespass-like theory.

In both cases, Justice Scalia wrote the majority opinion, paying little respect to the previously established Katz standard. In King, he did not discuss the issue, but at the oral argument, he applied the same trespass-ish analysis. When counsel for King referred to the reasonable expectation of privacy in genomic information, Justice Scalia suggested that the nature of the information was irrelevant because “You have a physical intrusion. You — you pull a guy's cheek apart and stick a — a swab into his mouth. That's a search — a reasonable expectation of privacy or not.”

The trespass-to-the-person notion is sufficient for disposing of the question in King itself, but the Maryland Court of Appeals used a more complex two-search theory. It claimed that “The first search is the actual swab of the inside of King's mouth and the second is the analysis of the DNA sample thus obtained, a step required to produce the DNA profile.” No justice endorsed this bifurcation. The bodily-invasion rationale was sufficient under both Katz and Jones-Jardines..

Stepping back from the precise facts in King, it is interesting to consider how the state could have responded if the dissenting view that the search was impermissible had prevailed. Could Maryland simply have adopted a less invasive mode of DNA collection, then argued that it was not undertaking a search at all? For example, would having a suspect merely touch a sticky pad (and thereby deposit enough cells for DNA profiling) constitute a search under the "physical intrusion onto the person" approach emphasized by Justice Scalia?

One might answer by paraphrasing the dissent’s “doubt that the proud men who wrote the charter of our liberties would have been so eager to [present] their [fingers] for royal inspection.” But that is no answer. These proud men also might not have been keen on sitting still for a photograph or a fingerprint for the King's men; yet, the dissent distinguished taking mug shots from collecting DNA samples “because that is not a Fourth Amendment search at all.” As for fingerprinting, the dissent stated that “our cases provide no ready answer to that question.”

Since photographing is not a search that triggers the Fourth Amendment’s protections, police should be free to use facial recognition software to check whether previous arrestees happen to match photos from a crime-scene (such as the Boston Marathon bombing)—even though they have no basis to suspect the many arrestees of that crime. But if fingerprints are the product of a suspicionless search, the same theory does not apply, and the Court would have to decide whether it is reasonable to trawl a database of latent prints from crime scenes to produce evidence against an arrestee. And if the dissenting Justices would accept the use of fingerprints to connect arrestees to unrelated crimes, why do the majority and the dissent disagree on the reasonableness of DNA collection and trawling? To answer these questions, we must move from the issue of defining the government activity that amounts to a search to the problem of evaluating the reasonableness of searches. As the majority observed, “To say that the Fourth Amendment applies here is the beginning point, not the end of the analysis.”

Maryland v. King No. 1: Quick Thoughts

After the oral argument in Maryland v. King, I wrote that "[i]n the end, my money is on a 5-4 (or maybe 6-3) decision for the state." Today the Supreme Court split into the two main camps I had described. The Court, in a rather staid opinion by Justice Kennedy, joined by Chief Justice Roberts and Justices Breyer and Thomas, upheld the Maryland law that requires individuals arrested and detained for major crimes to submit DNA samples that can be checked against a database of DNA profiles from unsolved crimes. Justice Scalia, wrote a bitter and sarcastic dissent for himself and Justices Ginsburg, Kagan, and Sotomayor.

Although the question is more delicately balanced than either opinion indicates, the majority reached the correct result. To be sure, not every state wants to establish arrestee DNA databases, and there is ample room to debate whether they represent the best use of scarce resources. But the constitution leaves the option open.

The contrary argument advanced by the dissent is that the Fourth Amendment always prohibits suspicionless entries into the body to investigate a crime. The dissenters would brand these searches as “unreasonable”—no matter how minor the intrusion on the person and no matter how much the program advances the welfare of the public. Justice Scalia tartly concludes that “the proud men who wrote the charter of our liberties would [not] have been so eager to open their mouths for royal inspection.”

Perhaps not, but if the only individual interest that demands protection is the slight discomfort of swabbing the inside of a cheek, a state could collect the DNA another way, perhaps by having the arrestee place his fingers not just on a fingerprint card, but also on a sticky pad.

Ultimately, a more sensitive understanding of the Fourth Amendment is required. It should be constitutionally reasonable to acquire, analyze, store, and search biometric data without a warrant and without individualized suspicion when five conditions hold: (1) the person legitimately is detained (or the data are acquired without confining the individual); (2) the process of collecting the data is not significantly physically or mentally invasive; (3) collection proceeds according to rules that prevent arbitrary selection of individuals; (4) the biometric data are used only to establish or authenticate the true identity of a given individual or to link individuals to crime scenes; and (5) the authentication or intelligence-gathering system is valid, reliable, and effective.

Fingerprinting of arrestees satisfies these conditions. So does photography, iris scanning, and noninvasive forms of DNA collection. The sticking point for many people is that the entirety of one’s DNA contains much more sensitive information. That is surely a legitimate concern, and it is why condition (4) is critical. Any system of DNA databanks for law enforcement—before or after conviction—must have rigorous safeguards to ensure access is confined strictly to biometric data that carry no deep threat to privacy.

Unfortunately, the Supreme Court did not analyze the issue in terms of a well-defined exception to the general rule of warrants and individual suspicion. The five justices in the majority engaged in what the dissent called "free-form" balancing—an approach that, in other circumstances, could be used to balance away important individual interests. Nevertheless, the entire Court agreed that DNA sampling on arrest—a procedure adopted by most of the states, the federal government, and many other technologically advanced countries—“will have the beneficial effect of solving more crimes.” Although the dissent correctly perceived that this is the main purpose of the Maryland law, the majority also emphasized the advantages of knowing whether an arrestee is implicated in other crimes in making decisions about pretrial detention.

The clash between the majority and minority in Maryland v. King leaves many questions unresolved:

● Just how long after an arrest must the state wait to collect the DNA? Maryland waits at least until formal charges are read at a judicial proceeding known as an arraignment.

● If an arrestee’s DNA is a near miss to a profile in the unsolved crimes database, can this fact be used to focus the investigation on his parents, children, or siblings who might be full matches? Maryland forbids such “familial searching.”

● May a state collect DNA from people arrested for more minor matters? The dissent complained that the Court’s logic would allow this, but the “free-form balancing” is a vague standard.

● What if future DNA genetic research overturns the Court’s characterization of the DNA features used for identification today as “junk”?

● If the dissent is right that “[n]early one-third of Americans will be arrested for some offense by age 23” (and if what is left unstated—that disproportionately many of these youths will be from African-American, Latino, and other minority groups”—also is true), would it not be fairer to collect DNA profiles from everyone?

One thing is clear. The legislatures and courts are not finished with the constitutional and policy questions surrounding DNA databases.

References

• Maryland v. King, No. 12-207 (U.S. June 3, 2013).
• Kaye, David H. 2013. "A Fourth Amendment Theory for Arrestee DNA and Other Biometric Databases." University of Pennsylvania Journal of Constitutional Law 15(4): 1095-1160.

Note: A condensed version of this posting appears in the BBC News blog, Viewpoints: Supreme Court and DNA Samples, BBC News: US and Canada, June 3, 2013.

People v. Garcia and Low Template DNA (LT-DNA)

Recent postings (March 27, May 25) about the appeal of Amanda Knox and Raffaele Sollecito suggested that the court’s decision not to order more DNA tests on the kitchen knife was less a manifestation of bad judicial mathematics than a judgment about the possible costs and benefits of additional low template (LT-DNA) testing as perceived by court-appointed experts. As a publication of the Royal Statistical Society noted last year, “Many questions at the extremities of LTDNA technology remain unanswered, and scientific disputes between experts are sometimes ventilated in litigation.” (Puch-Solis et al. 2012, at 85 ¶ 60.20, discussing English Court of Appeal cases in ¶¶ 60.21 & 60. 22).

In the United States, appellate courts have yet to address the admission of LT-DNA results. The latest opinion I have seen comes from a trial court in Bronx County, New York. In People v. Garcia, 39 Misc.3d 482, 963 N.Y.S.2d 517 (N.Y. Sup. Ct. 2013), a woman was found suffocated, with a sock in her mouth, and bound, with duct tape binding her face and limbs. Pablo Garcia was charged with her murder and related crimes. A piece of the duct tape contained DNA from at least two individuals. The New York City Office of the Chief Medical Examiner (OCME) reported that the mixture “is 586 times more probable if the sample originated from this defendant and one unknown, unrelated person than if it originated from two unknown, unrelated persons.”

Now, it is easy to see how a murderer applying the tape would leave some DNA on it, but why would there be additional DNA from an “unknown” rather than from the victim? One would think that duct tape used to bind an individual would include that person’s DNA rather than “one unknown, unrelated person.” However, it could be—I am speculating here—that the sample came from duct tape wrapped on top of other duct tape rather than a piece attached directly to the skin. Would the additional DNA profile have come from someone in the factory where the tape was made? From someone besides the murderer who touched its edges after the package had been opened? These are the kinds of possibilities that need to be considered when dealing with extremely small quantities of “contact DNA.”

Hoping to exclude the LT-DNA evidence, Garcia requested a pretrial hearing on whether the OCME’s protocols for typing LT-DNA and computing likelihood ratios were generally accpeted in the relevant scientific community. Judge Nicholas Iacovetta denied the request. He found that Garcia failed to raise much doubt about general acceptance. He wrote that “There is nothing new or novel about LCN DNA profiling. It simply represents the application of accepted and reliable procedures [like PCR and electrophoesis] that are applied in a modified manner.”

This reasoning, which has been used in previous cases, seems far too facile, After all,

PCR-based STR profiling with capillary electrophoreses is generally accepted for the purpose of producing identifying profiles because experiments have demonstrated its validity and it fits into well-established theories of chemistry and biology. It satisfies the validity standard of Daubert for the same reasons. But this foundation might not extend to the domain of the smaller samples. A light microscope works wells for studying bacteria but its magnification is not adequate for viewing much smaller viruses. For that purpose, an electron microscope is required. Radar can track airplanes or flocks of birds, but the signal-to-noise ratio is too low for it to be useful in tracking the flight path of a solitary, high-flying butterfly. The radar equipment is identical, and the operator is no less skilled at interpreting what he sees on the screen, but the procedure has not been validated (and would not be valid) for butterfly tracking.

Likewise, in the case of touch DNA, the relevant question is not whether the instrumentation and chemicals are identical or whether the analysts are using the same standards for interpretation. It is whether the system has been validated in the range in which it is being used. This is not a question about how well a validated or generally accepted procedure worked on a particular occasion ... . It is a ... question about the ability, under the best of conditions, of the equipment and its operators to pick out a weak but true signal from the noise. Until this trans-case question is resolved, admissibility is unjustified under Frye and Daubert.

Kaye, Bernstein and Mnookin (2011, § 9.2.3 at 428).

These observations do not necessarily mean that all forms of LT-DNA profiling--including the OCME's methodology--should be held inadmissible under the general acceptance standard for scientific evidence followed in New York. They simply mean that one must look to suitable experiments published in scientific journals or other places where they would be subject to critical review by other interested scientists, to the testimony or published views of appropriate scientists who have studied the matter, and to other indications of general acceptance.

Judge Iacovetta did some of this scrutiny and concluded “[s]eparately ... that LCN DNA testing conducted by OCME and its [statistical analysis] are both generally accepted as reliable in the forensic scientific community.”

The bases for this separate conclusion, however, are not uniformly compelling. First, the court pointed to “a lengthy Frye hearing” conducted by another trial court that determined “that LCN DNA testing ... when properly performed, ... is generally accepted as reliable in the scientific community.” Before accepting the conclusion of another judge who did conduct an evidentiary hearing, however, a court should ensure that the hearing actually aired the views of a cross-section of the scientific community. Especially in the early days of a scientific technique, imbalanced hearings are not uncommon. For examples in the DNA area, see Kaye (2010).

Second, the Garcia opinion stated that “[o]ther New York trial courts have also admitted LCN DNA results in evidence after denying defense requests for a Frye hearing ... LCN DNA testing has been admitted in New York State trial courts over 125 times, and in a federal district court in the Southern District of New York without a Frye hearing and in courts of multiple other countries including Germany, The United Kingdom, Sweden and Switzerland.” Again, a history of usage—especially without any hearings on the necessary foundational research and with no meaningful appellate review of the trial rulings—is a weak indicator of scientific acceptance.

Third, the court noted that “[a]lthough OCME is the only government facility currently using LCN DNA testing, several private and academic laboratories, such as the University of North Texas, use LCN DNA testing. OCME ... has been certified to conduct LCN DNA testing since 2005, using it to help identify the remains of victims of the World Trade Center terror attack in 2001 ... .” This is better. Usage of a method outside the courtroom, especially in matters that supply feedback on how well the method works, helps establish acceptance. (However, more details demonstrating the equivalence of the other uses to the one in Garcia itself would have been helpful.)

Fourth, the court observes that “OCME's own validation studies of LCN DNA testing ... were examined and certified by the New York State Commission On Forensic Science (NYSCFS) in 2005” and that “OCME is also audited yearly.” Favorable review by outside scientific staff of the commission and an auditing organization of a suitable set of the validity studies (as opposed to audits to show that the laboratory follows its protocols, investigates and corrects problems, and the like) argues in favor of general acceptance.

Finally, in discussing the software the OCME developed to help interpret mixed, partial DNA profiles from small samples, the opinion alludes to "peer reviewed articles in professional journals such as the International Journal of Forensic Genetics." I am not familiar with a journal by this name, and it does not seem to have a web site. Perhaps the court was referring to papers in Forensic Science International: Genetics (Mitchell et al. 2011; Mitchell et al. 2012). See also Caragine et al. (2009). The best evidence of general acceptance of validated technologies is publication in established scientific journals followed (ultimately) by a cessation of debate over the findings.The OCME publications support the laboratory procedures as well as the software for interpreting the data from those procedures.

Focusing on the software (named FST), Garcia states that

Other software programs such as True Allele, Life TD, Forenism, and Locomation, a software tool designed in the 1990's, also use Bayes Theorem to perform functions similar to the FST. The difference is that the FST uses empirically established drop-in and drop-out rates generated by thousands of tests, rather than just estimating them, which makes the FST more accurate as a predictor of likelihood ratios.

At the risk of quibbling (an occupational and personal hazard), these programs do not "predict likelihood ratios." If they predict anything, they predict genotypes, and which program's LRs best express the probative value of the inferred genotypes depends on more than how each program handles drop-in and drop-out probabilities.

To sum up, even if is wrong to regard the application of established technologies to LT-DNA as a trivial variation that requires no further legal scrutiny to establish admissibility, it also appears that one can make a reasonable case for general scientific acceptance of LT-DNA typing as required under New York law. The Garcia opinion shows how one trial judge was convinced.

References

• Caragine, Theresa, Rebecca Mikulasovich, Jeannie Tamariz, Ewelina Bajda, James Sebestyen, Howard Baum, and Mechthild Prinz 2009. "Validation of Testing and Interpretation Protocols for Low Template DNA Samples Using AmpF[ell]STR® Identifiler®." Croatian Medical Journal. 50(3): 250–267.
• Kaye, David H., David A. Bernstein, and Jennifer L. Mnookin 2011. The New Wigmore: A Treatise on Evidence: Expert Evidence, 2d ed., New York: Aspen.
• ----- 2010. The Double Helix and the Law of Evidence. Cambridge, MA: Harvard University Press.
• Mitchell, Adele A., Jeannie Tamariz, Kathleen O’Connell, Nubia Ducasse, Zoran Budimlija, Mechthild Prinz, and Theresa Caragine 2012. "Validation of a DNA Mixture Statistics Tool Incorporating Allelic Drop-out and Drop-in." Forensic Science International: Genetics 6: 749–761.
• Mitchell, Adele A., Jeannie Tamariz, Kathleen O‘Connell, Nubia Ducasse, Mechthild Prinz, Theresa Caragine 2011. "Likelihood Ratio Statistics for DNA Mixtures Allowing for Drop-out and Drop-in." Forensic Science International: Genetics Supplement Series 3: e240–e241
• Puch-Solis, Roberto, Paul Roberts, Susan Pope, and Colin Aitken 2012. Assessing the Probative Value of DNA Evidence: Guidance for Judges, Lawyers, Forensic Scientists and Expert Witnesses. London: Royal Statistical Society.

Bad Math or Passable Law? DNA Testing in the Continuing Prosecution of Amanda Knox and Raffaele Sollecito

In an previous posting, I raised some questions about an op-ed ("Justice Flunks Math") on the judge's refusal to depart from the court-appointed expert's written report in the prosecution of Amanda Knox and Raffaele Sollecito. This week, a flurry of opinionated comments appeared, and I let those that seemed to have at least some analysis or substance through the gate.

In my previous posting, I took issue with the op-ed's assertion that the trial judge "demonstrated a clear mathematical fallacy: assuming that repeating the test could tell us nothing about the reliability of the original results" and its apparent suggestion that retesting the same DNA sample would be comparable to testing a coin for bias by repeatedly tossing it. I argued that "[w]ithout some specification of precisely what made the initial testing problematic and whether those problems could be reduced sufficiently with retesting, it seems precipitous to convict the judge who overturned the guilty verdict of 'bad math.'"

Whatever the merits of the indictment of the judge, my thanks to those who offered information on whether retesting might be significantly more revealing than the initial testing. That is an interesting question in its own right.

In this regard, an author of the op-ed, Professor Leila Schneps kindly explained that the "confirming retest" (the phrase in her op-ed) did not mean a retest of the same sample (like flipping a coin again) but rather an analysis of a "new knife blade sample," a "rich sample ... from the place where the blade joins the handle of the knife." This new sample, she suggests, might be "positive for Meredith Kercher," in which case, "it would have correctly settled two of the questions left outstanding in the courtroom: was the first electropherogram showing the DNA on the knife correctly interpreted as Meredith's, and was Meredith's DNA actually on the knife?"

If we posit that the new sample is large enough to produce unambiguous results, then it could reveal whether "Meredith's DNA [was] actually on the knife." But Professor Schneps also states that the "rich sample" was "significantly lower than the quantity 'advised' by the kit, although the kit's website shows many examples of tests on smaller samples, some even smaller than the knife blade DNA, that gave positive and accurate results."

If the sample is this impoverished, are we not back in the realm of low-template DNA testing, where the worry is that stochastic effects can be dominant? The mathematical argument here seems to be that even though it might not be surprising to spot, by chance alone, some peaks in a new test that also are present in Meredith's genotype, the probability of those peaks plus the ones seen in the original testing of a different sample from the knife would be negligible unless Meredith's DNA was on the knife. In this way, the additional testing overcomes the low signal-to-noise ratio in each sample. That is a fair argument (as far as it goes), and the same logic underlies some protocols for testing contact DNA.

Still, given the difficulties and the level of discord over the best approaches to conducting and interpreting LT-DNA testing (see, e.g., A. Carracedo, P.M. Schneider, J. Butler & M. Prinz, Focus issue—Analysis and Biostatistical Interpretation of Complex and Low Template DNA Samples, Forensic Science International: Genetics 6 (2012) 677–678), and the court's experts' concerns about contamination, I wonder whether even the most mathematically erudite judge would have been so quick to order additional DNA testing in this case. Consequently, I am not yet prepared to give the judge a flunking grade for "a clear mathematical fallacy."

Potshots: “Blank Stares” and “No Data” on Latent Fingerprint Identification

According to as astute an observer as David Faigman,

In ... fields such as latent fingerprint identification, firearms, clinical psychology, and clinical psychiatry ... , if judges ask the question, “Where are the data?” they would be met with blank stares. If you ask a latent fingerprint examiner, “Where are your data?” the answer is likely to be, “Data. We have no data. In fact, we don't need data. We're specialists.” ... Many of these experts have been practicing their trade for twenty-five years; they know it when they see it. ... Under Daubert, however, even if your data happen to be experience, you have to be able to articulate how you came to know what you think you know. (Faigman 2013, 914).

A footnote explains that being “able to articulate how you came to know what you think you know” can be accomplished by “checking the basis for believing that the experience will produce reliable testimony.” (Ibid., 914 n. 64).

Now, I am no fan of claims of fingerprint examiners to be able to match latent prints to reference prints with absolute certainty (NIST 2012) and of lax and superficial court opinions allowing such testimony. (Kaye 2013; Kaye, Bernstein and Mnookin 2011). But the assertion that there are absolutely no data to show that latent print examiners can “produce reliable testimony” is too much for me to swallow. Indeed, in his treatise on scientific evidence, Professor Faigman does not insist that “no data” exist. The treatise correctly recognizes that “[a] few well-designed studies have now been conducted” (Faigman et al. 2012, § 33:56). To the list of six studies noted in the treatise (ibid., § 33.49 n. 10), one can add Tangen, Thompson, and McCarthy (2011). (As explained here last June, this Australian study showed a false negative rate of under 8% and a false positive rate of under 1% (Fingerprinting Error Rates Down Under, June 24, 2012)).

Perhaps Professor Faigman meant to say that even if data exist to support the judgments of fingerprint analysts—as they clearly do at a general level—a particular examiner’s judgments are not based on data, but on standardless, subjective impressions of the degree of similarity that warrants an identification or an exclusion. They just “know it when they see it.” That observation is closer to the mark (no pun intended). It is the gist of David Harris's contention that "most forensic science does not qualify as science in any true sense of that term." (Harris 2012, 36). Like Professor Faigman, Professor Harris complains that "[d]isciplines like fingerprint analysis, firearms tool-mark analysis, and bite-mark analysis have no basis in statistics, and do not originate in inquiry conducted according to scientific principles. Rather, they rely on human judgment grounded in experience ... without reference to rigorous and agreed-upon standards." (Ibid.) Identification experts who do not follow a protocol with quantitative or other external standards to achieve high inter-rater reliability should not insist that they are following the "scientific method." (Compare Kaye 2012, 123).

But "science" is not the only source of useful information, and experiments can measure the levels of accuracy for subjective as well as objective procedures. DNA laboratories have verified that DNA analysis performed in a specified way correctly distinguishes between samples taken from the same source and samples taken from different sources.  Indeed, this is the only sense in which it could be said that “DNA profiling [always] ... had known error rates” (Faigman 2013, 913). Even today, the error rates of DNA laboratories in actual case work is not really known. In the same manner, tests of fingerprint analyses performed by trained examiners show that they are capable of routinely distinguishing between marks taken from the same source and marks taken from different sources (with some errors). Again, however, we do not know the error rates of these examiners in actual case work. (Kaye 2012).

Consequently, appropriately documented latent print comparisons undertaken without unnecessary exposure to biasing information, presented with a recognition of the uncertainty in the largely subjective procedure and verified by an independent examiner blinded to the initial outcome as well as the output of an automated scoring system, should survive the “more rigorous test” (Faigman 2013) established in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), and embellished in later cases. Although there is ample room to improve fingerprint comparisons by human examiners and to implement automated systems for latent print work, “blank stares” and “no data” are no longer the only answers available to an objection under Daubert.

References

Faigman, David L. 2013. “The Daubert Revolution and the Birth of Modernity: Managing Scientific Evidence in the Age of Science.” University of California at Davis Law Review 46:893–930.

Harris, David A. 2012. Failed Evidence: Why Law Enforcement Resists Science. New York and London: New York University Press.

Kaye, David H. 2013. “Experimental and Scientific Evidence: Criminalistics.” In McCormick on Evidence, edited by Kenneth Broun, § 207. Eagan, MN: West Publishing Co.

Kaye, David H., ed. 2012. Expert Working Group on Human Factors in Latent Print Analysis, Latent Print Examination and Human Factors: Improving the Practice Through a Systems Approach. Gaithersburg: National Institute of Standards and Technology.

Kaye, David H., David E. Bernstein, and Jennifer L. Mnookin, 2011. The New Wigmore: A Treatise on Evidence: Expert Evidence. New York: Aspen Publishing Company, 2d ed.

Tangen, Jason M., Matthew B. Thompson, and Duncan J. McCarthy 2011. “Identifying Fingerprint Expertise.” Psychological Science 22:995 (available online).