Monday, March 24, 2014

What Is Wrong with People v. Lowe? More on DNA-on-Arrest Laws After Maryland v. King

Less than 24 hours before the U.S. Court of Appeals for the Ninth Circuit issued an opinion that avoided addressing the constitutionality of California's all-felony-arrest DNA database in the light of the Supreme Court's opinion in Maryland v. King, the California Supreme Court granted review to confront this question. The case, People v. Lowe, already has generated two opinions from California's Fourth District Court of Appeal.

In its first opinion, the California Court of Appeal concluded that
[T]he legitimate governmental interests promoted by the warrantless collection of DNA samples, including buccal swab samples, from felony arrestees who are taken into custody upon probable cause, far outweigh the arrestees' privacy concerns. Our conclusion is based on the following five reasons: The felony arrestee's diminished privacy interests; the de minimis nature of the physical intrusion involved in the collection of a buccal swab sample; the carefully limited scope of the DNA information that is extracted; the strict limits on the range of permissible uses of the DNA information obtained and the significant criminal penalties imposed upon those who violate those limitations; and the strong law enforcement interests in obtaining arrestees' identifying information, solving past and future crimes, deterring future criminal acts, and exonerating the innocent.
No. D059007, 2012 WL 5918717, Nov. 27, 2012, at *12 (unpublished opinion).

The California Supreme Court then directed the Court of Appeal to reconsider the matter in light of the U.S. Supreme Court's decision in Maryland v. King. See 165 Cal. Rptr. at *110. The Court of Appeal responded by recycling its original opinion with some quotations from King spliced in. It repeated the "five reasons" paragraph, moving a few words around. Id. at 121-22. It added four paragraphs to show that "[o]ur decision is consistent with the United States Supreme Court's recent majority decision in King," id. at 122, and called it a day.

Apparently, some of the California Supreme Court Justices believe that there is more to say about the possible distinctions between the Maryland law and the California one — either to establish that one some of the differences between the two laws matter or to confirm the Court of Appeal's conclusion that they do not.

Elsewhere, I have argued that the Supreme Court could invalidate a system like California's without overruling King (Kaye 2014). But I doubt that the Justices in the King majority would have any inclination to strike down any DNA-on-arrest law, and, as the latest Lowe opinion indicates, some of their statements in King make it easy to extend the case to California's law. 1/

Whatever lies behind the grant of review, the California Supreme Court can improve on the opinion in Lowe. First, it should not claim, as the Court of Appeal did, that "[t]he primary purpose of the amended DNA Act is to identify arrestees" in the sense of establishing who is who. Although California collection of DNA on arrest serves more than one purpose, the primary purpose of Proposition 69 is to solve and deter more crimes. 2/ Second, if the state supreme court chooses to include in a balancing test the value of capturing arrestees in the DNA database for solving crimes, it should recognize that this approach differs from the more contrived balancing in King. Third, if the supreme court does balance in this context, it should be careful about what it puts on each side of the balance. Thus, it should repudiate the view that arrestees have "diminished privacy interests." Their interests in privacy are no less valuable than anyone else's. The arrest is salient because it brings to bear state interests that would not otherwise be present, but it does not diminish the weight of anyone's Fourth Amendment interests. Fourth, the supreme court should avoid the Court of Appeal's incoherent reasoning about what triggers "totality of the circumstances" balancing. 3/ Finally, any opinion should avoid the phrase "junk DNA" and should describe the information content of DNA profiles in terms that are less easily confused with a different scientific issue (see Greely & Kaye 2014).

  1. See also Haskell v. Harris, No. 10-15152 (9th Cir. Mar. 20, 2014) (M. Smith, J., concurring)); Murphy (2013). 
  2. The Declaration of Purpose begins as follows: "Our communities have a compelling interest in protecting themselves from crime." Text of Proposed Laws, Proposition 69.
  3. The Court of Appeal first claimed, on the basis of the Supreme Court's anomalous opinion in Samson v. California, 547 U.S. 843 (2006), that "whether a particular search meets the reasonableness standard is judged by examining 'the totality of the circumstances.'" Then it contended that instead of judging whether every particular search is reasonable under so fluid a standard, the judgment is to made under the categorical rule that "[s]ubject only to a few well-delineated exceptions, warrantless searches are per se unreasonable under the Fourth Amendment." Then, it applied a balancing test, not at the level of a particular search, but at a programmatic level, to conclude that the California law satisfied the Fourth Amendment. Recognizing a categorical exception to the per se rule against warrantless searches would be one way to avoid such confusion. E.g., Kaye (2013).
Thanks to Erin Murphy for remarking on the grant of review in Lowe.
Previous Postings on the Aftermath of Maryland v. King

Previous Postings on the Opinions in Maryland v. King
  • Maryland v. King No. 1: Quick Thoughts, June 3, 2013,
  • Maryland v. King No. 2: Was There a Search?, June 7, 2013,
  • Maryland v. King: Interlude, June 9, 2013,
  • Maryland v. King No. 3: Bertillonage as Precedent, June 12, 2013,
  • Maryland v. King: A Digression on Ellipses, Actual Innocence, and Dr. Mengele, June 13, 2013,
  • Maryland v. King: “Quite a Worldview”, June 15, 2013,
  • Maryland v. King: The Tenth Justice (Stevens) Votes, June 15, 2013,
  • Maryland v. King: When Being Smart and Witty Is Not Enough, Nov. 27, 2013,
  • Maryland v. King: The Dissent's Ten Second Rule, Nov. 29, 2013,
  • Blast Off for King from Florida's Space Belt? Not Quite, Feb. 26, 2014,

Saturday, March 22, 2014

The Ninth Circuit's Minimal Opinion in Haskell v. Harris

Two days ago, eleven judges of the Ninth Circuit issued a long awaited opinion in Haskell v. Harris. 1/ The en banc court ruled against the plaintiffs challenging California's DNA-on-arrest law. However, the court did not address their arguments and has not ended the case one way or the other.

Instead, the court simply said that the Supreme Court's opinion last June in Maryland v. King 2/ means that at least some applications of the California law are constitutional; consequently, "plaintiffs cannot show that the district court abused its discretion in denying a preliminary injunction that would apply to the entire class." The court’s final words were "[i]f plaintiffs believe they're entitled to a preliminary injunction as to a smaller class, they are free to seek it from the district court and we will review it if and when it is presented to us."

The Wrong Class -- or the Wrong Relief?

There is a problem with this logic, at least as the court expressed it. The certified class included “[a]ll persons who are, or will be, compelled to submit to the search and seizure of their body tissue and DNA . . . solely by reason of the fact that they have been arrested for, or charged with, a felony offense by California state or local officials.” As to some members of this class, the en banc court indicated, DNA sampling, analysis, and trawling clearly would be permissible under King. But what could the smaller class be? Who are the people arrested in California who "clearly" are constitutionally subject to DNA sampling and retention as it is done in California?

The en banc court gives no answer, but King most clearly applies when:
The DNA sampling [is] confined to violent crimes and burglaries; officials [have] no discretion to pick and choose which arrestee’s DNA to acquire; a physical intrusion into the body [takes] place; the loci tested reveal[] no sensitive medical or other privacy-laden information; the state trawl[s] the forensic index (of unsolved crime scene profiles) only for matches to the arrestee (and not for partial matches that might point primarily to immediate relatives); the profiling and uploading occur[s] after formal charges; and the samples are destroyed if a conviction does not ensue. 3/
The people in these conditions cannot be part of a class entitled to any relief. However, this excludes, well, no one in California. Even people arrested for violent crimes and burglaries (as in Maryland) are at risk for familial searching (although the Haskell plaintiffs did not rely on this concern as a basis for distinguishing King), and they are not entitled to automatic destruction of samples (as are arrestees in Maryland). Moreover, everyone arrested in California for any felony could have a sample analyzed and the profile trawled before any judge agrees with the state that there is at least probable cause to believe that the arrestee has committed a felony.

Given this set of arguably distinguishing factors, it is not so obvious what "smaller class" the court had in mind. Even after King, the class need not change, but the injunction (if one were warranted) would have to be tailored to different subclasses. For example, arrestees charged with violent crimes or burglaries would not be entitled to the blanket order that plaintiffs requested back in 2009. At that time, plaintiffs asked the district court to "enjoin[] Defendants ... from the compulsory search, seizure, collection, analysis, and/or retention of biological samples from any member of the Plaintiff Class ... until and unless he or she is actually convicted of a felony offense, unless such search, seizure, collection, analysis, and/or retention is supported by a warrant issued on probable cause ... ." 4/ But the entire class still might be entitled to some relief. If we were to suppose that no departure from the Maryland law were permissible —which is the most that the California plaintiffs could hope for — even California arrestees charged with Maryland-type felonies would be entitled to an order requiring the state (1) to delay that profiling and uploading until they are bound over for trial, (2) to destroy their DNA samples if they are not convicted, and (3) to refrain from using their profiles in familial searches.

Because plaintiffs sought only a one-size-fits-all injunction, and that size was too big, the district court correctly denied that particular relief. But variable relief would be consistent with plaintiffs' theories of the Fourth Amendment. This, I think, is what the en banc court was getting at in referring to a smaller class. And, if the court reached a consensus solely on this procedural ground, then it is appropriate to allow plaintiffs to amend their complaint in light of King. 5/

A Concurring Opinion

One judge already disagrees with this construction of the per curiam opinion. Judge Milan Smith, who wrote the panel opinion upholding the California law well before Maryland v. King, 6/ read “the per curiam opinion [as holding] that California's DNA collection law is clearly ‘constitutional as applied to anyone arrested for, or charged with, a felony offense by California state or local officials.’” (Emphasis added).

I doubt that this is a correct reading of the per curiam opinion, but I have to say that the other judges could have been clearer about their desire to avoid opining on the limits of King. The other en banc judges wrote that the case turned on the answer to the question, "Is California's DNA collection scheme constitutional as applied to anyone 'arrested for, or charged with, a felony offense by California state or local officials?'" The answer, they claimed, "is clearly yes." So does "anyone" really mean "everyone," as Judge Smith claims, or does it mean "at least one," as I thought when I first read the per curiam opinion? Only the latter interpretation can be reconciled with the court's willingness to countenance a narrower class action.

Judge Smith denied that a complaint on behalf of a narrower class (or, better, a request for a more nuanced injunction) is viable. Surely, he contended, King decided all these fine points in favor of the state. The arguments in his concurring opinion, however, are not uniformly compelling.

Judge Smith wrote that "[t]he majority in King expressly recognized that its decision 'implicates more than the specific Maryland law.'" 7/ But this observation hardly means that every variation of arrestee sampling in existence in 2013 is constitutional under the inherently vague balancing test adopted by the majority. Of the 28 states with arrestee DNA laws, "11 states require an arraignment or judicial determination of probable cause before a sample can be collected or analyzed." 8/ Suppose that the opinion in King had explicitly announced that this provision is essential to a finding of Fourth Amendment reasonableness. That would have contradicted Judge Smith's understanding of the opinion, but the decision still would have "implicate[d] more than the specific Maryland law." It would have pulled the rug out from under 17 states.

Thus, it is a stretch to infer from the King court's recognition of the obvious — that it was deciding a case of national interest — that is also was deciding on the propriety of every existing DNA-on-arrest law. That is not how the Anglo-American system of case-by-case adjudication works.

Neither does the concurrence gain much mileage from "the sky is falling" rhetoric in the King dissent. Judge Smith accepted at face value Justice Scalia's protestation that the result in King could be — indeed, would have to be — extended to reach the most minor of arrests. In oral argument, Judge Smith suggested that Justice Scalia had to be right. After all, said Judge Smith, "he was in the conference, he heard what the majority decided, and that's how he reads it. How can we read it otherwise?" 9/ Yet, it is a standard ploy of dissenting opinions to exaggerate the scope or sweep of the opinion they oppose, and Justices who participated in a conference on a case frequently disagree over the import of the opinions that eventually emerge.

That said, Judge Smith may well be correct in a Legal Realist sense. It is doubtful that the Justices in the majority in King would respond very differently to the other state laws. 10/ Given the phrasing in Justice Kennedy's opinion, the Chief Justice's earlier stay of the Maryland Court of Appeals decision, and the remarks of several Justices at the oral argument in King, it seems likely that those Justices would have no problem using their balancing test to uphold the California law despite all its differences from the Maryland's law. For the Ninth Circuit to have written an opinion striking down parts of California's system of DNA database system would have perilous. Nevertheless, the court of appeals has left the door open to doing so in this four-and-a-half-year-old case.

  1. No. 10–15152, 2014 WL 1063399 (9th Cir. Mar. 20, 2014) (en banc). The 11 judges, selected at random from the full court, are Chief Judge Alex Kozinski and Judges Harry Pregerson, M. Margaret McKeown, Raymond C. Fisher, Ronald M. Gould, Richard A. Paez, Richard C. Tallman, Johnnie B. Rawlinson, Milan D. Smith, Jr., N. Randy Smith and Paul J. Watford.
  2. 133 S.Ct. 1958 (2013).
  3. David H. Kaye, Why So Contrived? The Fourth Amendment Balancing, Per Se Rules, and DNA Databases After Maryland v. King, 104 J. Crim. L. & Criminology (forthcoming 2014).
  4. Class Action Complaint for Declaratory and Injunctive Relief, Haskell v. Brown, Oct. 7, 2009, at 22-23.
  5. Of course, the ACLU, which represents the plaintiffs, might conclude that it has no chance of prevailing on the theory that states cannot relax a single one of the various limitations written into Maryland's law. For instance, it might give up on those people who are charged with violent crimes or burglaries and contend only that individuals arrested for less serious felonies cannot have their DNA analyzed and uploaded before a judge determines that probable cause is present. This certainly would result in a narrower class. But the court's premise that a subclass of arrestees in California are identical to arrestees in Maryland is faulty. Because the California system does not include automatic sample destruction, everyone whose DNA has been collected on arrest in California has been treated differently. The opinion does not state that this is an insignificant difference, but unless that is what it means, it is hard to see why the ACLU must plead for a narrower class.
  6. Haskell v. Harris, 669 F.3d 1049 (9th Cir. 2012). For criticism of Judge Smith’s theory that “the Constitution's plain text” dictates “the ‘totality of the circumstances’ balancing test to determine whether a warrantless search is reasonable,” id. at 1053–54, see David H. Kaye, On the “Considered Analysis” of DNA Collection Before Conviction, 60 UCLA L. Rev. Disc. 104 (2013).
  7. The majority wrote that
    Twenty-eight States and the Federal Government have adopted laws similar to the Maryland Act authorizing the collection of DNA from some or all arrestees. See Brief for State of California et al. as Amici Curiae 4, n. 1 (States Brief) (collecting state statutes). Although those statutes vary in their particulars, such as what charges require a DNA sample, their similarity means that this case implicates more than the specific Maryland law. At issue is a standard, expanding technology already in widespread use throughout the Nation.
    Maryland v. King, 133 S.Ct. 1958, 1968 (2013). The technology of STR typing is standard and in widespread use, as are computer-searchable databases of the resulting profiles, but this does not make every use of the technology constitutionally acceptable. That the majority referred to the charges that trigger DNA collection as a "particular" that varies among states could signal that these Justices did not think it was terribly important, but the remark does not transform a dictum into a holding and does not mean that every variation is so benign as to be "not constitutionally relevant." Haskell, No. 10–15152, 2014 WL 1063399 (9th Cir. Mar. 20, 2014) (Smith, J., concurring).
  8. Nat'l Inst. of Justice, DNA Sample Collection from Arrestees, Dec. 7, 2012,
  9. C-SPAN, Haskell v. Harris Oral Arguments, Dec. 9, 2013, at 6 min. 34 sec.,
  10. Erin Murphy, License, Registration, Cheek Swab: DNA Testing and the Divided Court, 127 Harv. L. Rev. 161 (2013).

Thanks to Hank Greely and Erin Murphy for emails on these latest opinions in Haskell.
Previous postings on Haskell v. Harris
Previous postings on the opinions in Maryland v. King
  • Maryland v. King No. 1: Quick Thoughts, June 3, 2013,
  • Maryland v. King No. 2: Was There a Search?, June 7, 2013,
  • Maryland v. King: Interlude, June 9, 2013,
  • Maryland v. King No. 3: Bertillonage as Precedent, June 12, 2013,
  • Maryland v. King: A Digression on Ellipses, Actual Innocence, and Dr. Mengele, June 13, 2013,
  • Maryland v. King: “Quite a Worldview”, June 15, 2013,
  • Maryland v. King: The Tenth Justice (Stevens) Votes, June 15, 2013,
  • Maryland v. King: When Being Smart and Witty Is Not Enough, Nov. 27, 2013,
  • Maryland v. King: The Dissent's Ten Second Rule, Nov. 29, 2013,
  • Blast Off for King from Florida's Space Belt? Not Quite, Feb. 26, 2014,

Saturday, March 15, 2014


According to Wikipedia, "MDNA may refer to
-Mitochondrial DNA (mDNA or mtDNA), the DNA located in organelles called mitochondria
-MDNA (album), a 2012 album by Madonna
-MDNA Tour, 2012 concert tour by Madonna."
Additional research reveals an unexpected relationship between the first and third expansions of the acronym. If Madonna has anything to say about it, her fans seeking unusual souvenirs will have neither mDNA nor any other DNA from the aging pop star on the MDNA tour. She has a "sterilization team" to extirpate any DNA in her dressing room after shows. In fact, the team is concerned with much more than DNA. They remodel the dressing room to include "fake ceilings and fake walls, so they can ensure that no one has hidden a camera somewhere." [1] No "genetic exceptionalism" here.

I have heard that the Secret Service collects the plates, silverware, and drinking glasses or cups the President uses when he is on tour.1/ How about the rest of us? Do we have a reasonable expectation that police will not collect our shed DNA? No court has held that the investigative technique is a search within the meaning of the Fourth Amendment.

  1. The newsletter, DNA: Focus, available from the ACLU of Vermont at, attributes this claim "to the British newspaper, The Sunday Mirror," but a quick web search failed to confirm that the Sunday Mirror or any other publication has made such a statement.
  1. Bang Showbiz, Madonna Has DNA Cleaning Team for Tour, Winnipeg Free Press, June 22, 2012
Related postings
Keywords: Abandoned DNA, shed DNA, Madonna

A "Ridiculous" Fourth Amendment Argument in the Grim Sleeper Case?

On January 7, Los Angeles Superior Court Judge Kathleen Kennedy dismissed as "specious and ridiculous" one argument from the alleged "Grim Sleeper" serial killer Lonnie Franklin Jr. [1] According to Mr. Franklin's lawyers, the police violated his Fourth Amendment right to be free from unreasonable searches and seizures when they surreptitiously acquired and analyzed DNA that he left on his plate and utensils at a restaurant.

This is not the first notorious case in which Judge Kennedy has participated. In the prosecution of O.J. Simpson, when she was a municipal judge, she initially limited investigators to 10 hairs from Mr. Simpson's head for microscopic comparisons to hairs found in a blue knit cap lying near the bodies of Nicole Brown Simpson and Ronald Goldman. That "surreal" ruling reflected a lack of understanding of hair comparison protocols. [2, p. 230] However, the Grim Sleeper ruling is more mainstream. No court has treated collecting shed or inadvertently abandoned DNA as a search [3, p. 454]

Apparently, investigators did not want to alert Mr. Franklin that he was suspected of the long series of rapes and murders attributed to the Grim Sleeper. They had a police officer pose as a busboy at John's Incredible Pizza, where Franklin was attending a birthday party. Franklin argued that the officer-busboy cleared his plates — first pizza and then chocolate cake — before he had finished eating. and that this poor service made the collection unconstitutional.

One might not think much would turn on how close Franklin was to completing his repast. From time to time, I have had to tell an eager waiter reaching for my plate to wait -- I am not yet done. If a customer does not speak up, how can he be said to have a protected property interest in the plate, an interest that might trigger Fourth Amendment protection under United States v. Jones, 132 S.Ct. 945 (2012)? Moreover, if a failure to allow the restaurant patron time to eat all he wants is the source of the Fourth Amendment violation, the inevitable discovery exception to the warrant requirement could render the matter academic.

However, Franklin also claimed that he had a reasonable expectation that his plates would be thrown into a pile with others, making his DNA unavailable for testing. This is precisely the argument that the Supreme Court rejected in a questionable opinion in California v. Greenwood, 486 U.S. 35 (1988). In that case, police acquired sealed, plastic bags of trash that their suspect placed on the curb for municipal pickup. Greenwood argued that he expected that the bags would be mixed up with the other garbage in the neighborhood, preserving his privacy interest in the contents of his bags. But the majority of the Court deemed this expectation unreasonable because marauding dogs or curious people might go through the bags before the garbage truck arrived.

Even if that reasoning is convincing, however, the burden on the diner to take other steps to protect his DNA from inspection seems greater than that which Greenwood imposes on people to dispose of some parts of their trash privately. Judge Kennedy reportedly reasoned that "If [Franklin] were really concerned about such things, he would not eat or he would take his trash with him." [1] Is that the kind of world we want to have — one in which people who wish to keep their DNA to themselves must bring their own silverware, plates, and trash bags to restaurants or stay at home for all meals?

Thus, I think that the Fourth Amendment status of police collection of certain forms of shed or discarded DNA is a closer question that the caselaw suggests. There is a plausible argument that at least some surreptitious DNA collection from suspects amounts to a "search." Accepting this argument would not necessarily make this mode of DNA collection and analysis impermissible, for not all searches are unreasonable. But it would require more analysis of the individual and state interests at stake.

  1. Paresh Dave, Grim Sleeper: Judge Allows DNA Evidence Gathered at Restaurant, Los Angeles Times, Jan. 7, 2014
  2. David H. Kaye, The Double Helix and the Law of Evidence (2010)
  3. Albert E. Scherr, Genetic Privacy and the Fourth Amendment: Unregulated Surreptitious DNA Harvesting, 47 Ga. L. Rev. 445 (2013)
Related postings
  • MDNA, Forensic Science, Statistics, and the Law, Mar. 15, 2014
Key words: Abandoned DNA, Fourth Amendment, Surreptitious DNA collection, Greenwood, Franklin, Grim Sleeper, Kennedy, Los Angeles

Wednesday, February 26, 2014

Blast Off for King from Florida's Space Belt? Not Quite

In Maryland v. King,1/ the Supreme Court upheld the constitutionality of taking DNA from individuals merely arrested of crimes. The majority relied on the perceived value of DNA profiling following by trawls of DNA databases of profiles from unsolved crimes to inform bail determinations and other pretrial decisions. The idea is that the arrestee might be linked to an unsolved crime, which would be good to know before critical decisions are made or become irrevocable.

Although such pretrial hits to unrelated crimes are rarely made with lightning speed, the Court suggested that this situation could change (just as it did with the introduction of computerized fingerprint matching). The majority wrote that:
[T]he FBI has already begun testing devices that will enable police to process the DNA of arrestees within 90 minutes. ... . An assessment and understanding of the reasonableness of this minimally invasive search of a person detained for a serious crime should take account of these technical advances. ... New technology will only further improve its speed and therefore its effectiveness.2/
Yesterday, Florida’s Space Coast Daily newspaper announced a “first-ever application of rapid DNA technology.”3/ “In January 2014,” police in the city of Palm Bay, south of Melbourne, “began processing samples from active cases” with IntegenX’s RapidHIT 200 device for producing STR profiles in about 90 minutes. They struck paydirt in the investigation of a September 2013 home burglary that netted “approximately $30,000 worth of property including firearms, electronic equipment, computers, TV’s, military equipment including a bulletproof vest, clothing, several guitars and even the cable box.”

Despite the "first-ever" buzz, other localities are using the same technology operationally. In South Carolina, for example, it fingered "one of three suspects in a string of burglaries in northeast Richland County from December 2013 to February 2014."4/

Does this mean that the Court’s prediction has come true, that arrestee DNA is being processed within a two-hour window? Hardly. The Palm Bay case concerned an individual who already had been “arrested for the crime based on witness statements and other evidence. A blood sample taken from the scene was run through the RapidHIT 200 which yielded a profile that matched the same suspect who had been arrested and charged with the crime.” This is not a case in which an automated, rapid system for DNA profiling was applied to acquire an arrestee profile for checking against a DNA database for unsolved crimes, as the King Court contemplated.

Nevertheless, when validated, the rapid processing power certainly can be applied to arrestee samples. Those are easier to analyze than are the often messier crime-scene samples that the Palm Bay police are profiling with the technology. The Court’s prediction may seem space age, but it is not particularly futuristic.

Indeed, the article goes on to suggest that by uploading the RapidHIT profiles into a local database of “Palm Bay and several local agencies, including Melbourne, West Melbourne and Cocoa Police,” police in the region are in a position to identify “suspects who cross jurisdictions to commit their crimes.” Of course, this is what Florida’s SDIS (State DNA Index System) does. Presumably, the objective of these police agencies is to do it more nimbly and quickly. Yet, that, in turn, creates alarms about “rogue databases” operating outside a statutory framework.


"IntegenX Inc. has met the FBI guidelines to upload directly to the NDIS system known arrestee and convicted offender DNA profiles, as well as casework known samples, generated with the RapidHIT System using Life Technologies GlobalFiler Express kits from Thermo Fisher Scientific." IntegenX Inc., RapidHIT System Approved to Upload DNA Profiles to National Database, Forensic Mag.,
Mar. 19, 2014.


1. 133 S.Ct. 1958 (2013).
2. Id. at 1977.
3. Palm Bay Police Nail Crooks With DNA Evidence, Space Coast Daily, Feb. 25, 2014,
4. Cassie Cope, Richland Sheriff’s Department’s New Machine Analyzes DNA in 90 Minutes, State (S.Car.), Feb. 27, 2014,

Previous Postings on the Opinions in Maryland v. King

Sunday, January 26, 2014

Hundreds of Errors in DNA Databases: What Do They Mean?

The other day, the New York Times reported that "[t]he Federal Bureau of Investigation, in a review of a national DNA database, has identified nearly 170 profiles that probably contain errors" and that "New York State authorities have turned up mistakes in DNA profiles in New York’s database."

Apparently, nearly all the errors involve a recorded profile that differs from the true profile at one (and only one) allele. These "mistakes were discovered in July, when the F.B.I., using improved software, broadened the search parameters used to detect matches. The change, one F.B.I. scientist said, was like upgrading or refining 'a spell-check.' In 166 instances, the new search found DNA profiles in the database that were almost identical but conflicted at a single point."

This discovery raises several questions. How prevalent are these errors? What caused them? And, what investigative or prosecutorial errors could they cause?

I. Prevalence and Causes

The article observes that "[t]he errors identified so far implicate only a tiny fraction of the total DNA profiles in the national database, which holds nearly 13 million profiles, more than 12 million from convicts and suspects, and an additional 527,000 from crime scenes." Thus, "Alice R. Isenberg, the chief of the biometric analysis section of the F.B.I. Laboratory, said that ... 'We were pleasantly surprised it was only 166. ... These are incredibly small numbers for the size of the database.'" She believes "most of the 166 cases probably resulted from interpretation errors by DNA analysts or typographical errors introduced when a lab worker uploaded the series of numbers denoting a person’s DNA profile."

II. Consequences: Risks of False Hits and Misses

It is true that 166 is a small fraction--about 0.0013%--of all the profiles on record. But it would be interesting to know whether these discrepancies are concentrated in the known offender or arrestee profiles or in the ones from crime scenes (the "forensic index").

A. Errors in the Offender-arresstee Indices

Suppose first that the profile of an individual in an offender or arrestee index departs from the true profile of that individual by a single allele. If that individual committed an offense for which a crime-scene profile is recovered, he would not be noticed in a database trawl (unless the search program flagged near misses like this). This would be a false negative error.

How probable is this false negative error? There have been less than 230,000 hits (see between profiles in the forensic index and the more than 12,000,000 profiles in the offender and arrestee indices. This means that an individual has about a 1.9% chance of being linked to a crime through the database. Assuming that all 166 misrecorded or mistyped profiles are in the offender-arrestee indices, it follows that the probability that one or more of these errors would yield a false negative is 166 x 0.0013% x 1.9% = 0.000042 = 0.0042%. Even if the 166 errors were the tip of the proverbial iceberg, 90% of which lies below the visible surface, the probability of a false negative resulting from the inaccurate profiles is only 0.042%.

If the inaccurate profile pertains to a offender or an arrestee, as we have assumed so far, then the probability of a false positive -- a hit to an individual represented in the database who is not the source of the crime-scene sample -- typically is even smaller. A false positive could occur if someone else in the world has a true profile that (1) is not in the offender-arrestee index and (2) perfectly matches the inaccurate profile in the index. Because all DNA profiles consisting of substantial number of loci are rare, the probability of a false positive must be small. 1/

B. Errors in the Forensic Index

Of course, all the inaccurate profiles did not come from previous offenders or arrestees. Some came from the crime-scene samples -- producing erroneous entries in the forensic index. These errors "had the effect of obscuring clues, blinding investigators to connections among crime scenes and known offenders" in three cases in New York. When forensic-index errors are present, the risk of a false negative error is much larger. Even if the source of the crime-scene sample is represented in the offender-arrestee indices (as seems to occur for some 2% of these database inhabitants), a database trawl for a match to the erroneous forensic index profile will miss this person.

Again, however, the chance of a false positive -- a hit between the false crime-scene profile and an offender or arrestee profile -- remains low for full DNA profiles. The probability of another person having the same false profile is still quite small. 2/

III. Caveats

The probabilities noted here are the result of back-of-the-envelope calculations (see note 1). Although I would think that more precise analyses would not give dramatically different results, I am not suggesting that the sources of errors reported by the FBI should be ignored or minimized. The incidence of errors in generating and recording data can be reduced, in part by automated systems. 3/ In addition, the estimates I have provided do not pertain to errors resulting from contamination of a crime-scene sample with an innocent suspect's sample and to profiles that are less complete than thirteen loci.

  1. If each STR allele is present in 10% of the relevant population (the actual values for each allele will vary from case to case) and if 13 loci are in the profile (the current norm), then the probability of a full match to the source of a crime-scene sample is less than (2 x 1/10)13 = 0.00000000082 (if the source of the crime-scene sample and the database inhabitant are unrelated members of a population in Hardy-Weinberg equilibrium and there is no linkage disequilibrium). Even if the correctly profiled crime-scene sample comes from a brother, the probability of a 13-locus match is only about (1/4 + p/2 + 2p2)13, where p is the average chance that the two alleles will match (the proportion of homozygotes in the population). (National Research Council Committee on DNA Technology in Forensic Science 1992, p. 167). If the homozygosity rate is, say 30% (which is higher than that reported in Budowle et al. (1999, p. 1278 (tbl. 1)), the probability of a full sibling possessing a one-off profile would only be about 0.00084.
  2. See supra note 1.
  3. Additional recording errors might be detected by massive, all-pairs trawls of the indices in CODIS. These would flag suspiciously similar profiles recorded as coming from what are thought to be different sources.


Saturday, January 18, 2014

The Signal, the Noise, and the Errors

Published in September 2012, The Signal and the Noise by Nate Silver soon reached The New York Times best-seller list for nonfiction. named it the best nonfiction book of 2012, and it won the 2013 Phi Beta Kappa Award in science. Not bad for a book that presents Bayes' rule as prescription for better thinking in life and as a model for consensus formation in science. The subtitle, for those who have not read it, is "Why So Many Predictions Fail--But Some Don't," and the explanations include poor data, cognitive biases, and statistical models not grounded in an understanding of the phenomena being modeled.

The book is both thoughtful and entertaining, covering many fields. I learned something about meteorology (your local TV weather forecaster probably is biased toward forecasting bad weather--stick to the National Weather Service forecasts), earthquake predictions, climatology, poker, human and computer chess-playing, equity markets, sports betting, political polling and poor prognostication by pundits, and more. Silver does not pretend to be an expert in all these fields, but he is perceptive and interviewed a lot of interesting people.

Indeed, although Wikipedia describes Silver as "an American statistician and writer who analyzes baseball (see Sabermetrics) and elections (see Psephology)," he does not present himself as as expert in statistics, and statisticians seem conflicted on whether to include him their ranks (see AmStat News). He seems to be pretty much self-educated in the subject, and he advocates "getting your hands dirty with the data set" rather than "spending too much time doing reading and so forth." Frick (2013).

Perhaps that emphasis, combined with the objective of writing an entertaining book for the general public, has something to do with the rather sweeping--and sometimes sloppy--arguments for Bayesian over frequentist methods. Although Silver gives a few engaging and precise examples of Bayes' rule in operation (playing poker or deciding whether your domestic partner is cheating on you, for instance), he is quick to characterize a variety of informal, intuitive modes of combining many different kinds of data as tantamount to following Bayes' rule. Marcus & Davis (2013) identify one telling example--a very successful sports bettor who recognizes the importance of data that the bookies overlook, misjudge, or do not acquire . (Pp. 232-61). What makes this gambler a Bayesian? Silver thinks it is the fact that "[s]uccessful gamblers ... think of the future as speckles of probability, flickering upward and downward like a stock market ticker to every new jolt of information." (P. 237). That's fine, but why presume that the flickers follow Bayes' rule as opposed to some other procedure for updating beliefs? And why castigate frequentist statisticians, as Silver seems to, as "think[ing] of the future in terms of no-lose bets, unimpeachable theories, and infinitely precise measurements"? Ibid. Surely, that is not the world in which statisticians live.

Changing probability judgments does not make someone a Bayesian

In proselytizing for Bayes' theorem and in urging readers to "think probabilistically" (p. 448), Silver also writes that
When you first start to make these probability estimates, they may be quite poor. But there are two pieces of favorable news. First, these estimates are just a starting point: Bayes's theorem will have you revise and improve them as you encounter new information. Second, there is evidence that this is something we can learn to improve. The military, for instance, has sometimes trained soldiers in these techniques,5 with reasonably good results.6 There is also evidence that doctors think about medical diagnoses in a Bayesian manner.7 [¶] It is probably better to follow the lead of our doctors and our soldiers than our television pundits.
It is hard to argue with the concluding sentence, but where is the evidence that many soldiers and doctors are intuitive (or trained) Bayesians? The report cited (n.5) for the proposition that "[t]he military ... has sometimes trained soldiers in the [Bayesian] techniques" says nothing of the kind.* Similarly, the article that is supposed to show that the alleged training in Bayes' rule produces "reasonably good results" is quite wide of the mark. It is a 35-year-old report for the Army on "Training for Calibration" about research that made no effort to train soldiers to use Bayes' rule.**

How about doctors? The source here is an article in the British Medical Journal that asserts that "[c]linicians apply bayesian reasoning in framing and revising differential diagnoses." Gill et al. (2005). But these authors--I won't call them researchers because they did no real research--rely only on their impressions and post hoc explanations for diagnoses that are not expressed probabilistically. As one distinguished physician tartly observed, "[c]linicians certainly do change their minds about the probability of a diagnosis being true as new evidence emerges to improve the odds of being correct, but the similarity to the formal Bayesian procedure is more apparent than real and it is not very likely, in fact, that most clinicians would consider themselves bayesians." Waldron (2008, pp. 2-3 n.2).

The transposition fallacy

Consistent with this tendency to conflate expressing judgments probabilistically with using Bayes' rule to arrive at the assessments, Silver presents probabilities that have nothing to do with Bayes' rule as if they are properly computed posterior probabilities. In particular, he naively transposes conditional probabilities to misrepresent p-values as degrees of belief.

At page 185, he writes that
A once-famous “leading indicator” of economic performance, for instance, was the winner of the Super Bowl. From Super Bowl I in 1967 through Super Bowl XXXI in 1997, the stock market gained an average of 14 percent for the rest of the year when a team from the National Football League (NFL) won the game. But it fell by almost 10% when a team from the original American Football Leage (AFL) won instead. [¶] Through 1997, this indicator had correctly “predicted” the direction of the stock market in twenty-eight of thirty-one years. A standard test of statistical significance, if taken literally, would have implied that there was only about a 1-in-4,700,000 possibility that the relationship had emerged from chance alone.
This is a cute example of the mistake of interpreting a p-value, acquired after a search for significance, as if there had been no such search. As Silver submits, "[c]onsider how creative you might be when you have a stack of economic variables as thick as a phone book." Ibid.

But is the ridiculously small p-value (that he obtained by regressing the S&P 500 index on the conference affiliation of the Super Bowl winner) really the probability "that the relationship had emerged from chance alone"? No, it is the probability that such a remarkable association would be seen if the Super Bowl outcome and the S&P 500 index were entirely uncorrelated (and no one had searched for a data set that shared a seemingly shocking correlation to the S&P 500 index). Silver may be a Bayesian at heart, but he did not compute the probability of the null hypothesis given the data, and it is problematic to tell the reader that a "standard test of statistical significance" (or more precisely, a p-value) gives the (Bayesian) probability that the null hypothesis is true.

Of course, with such an extreme p-value, the misinterpretation might not make any practical difference, but the same misinterpretation is evident in Silver's characterization of a significance test at the 0.05 level. He writes that "[b]ecause 95 percent confidence in a statistical test is Fisher’s traditional dividing line between 'significant' and 'insignificant,' researchers are much more likely to report findings that statistical tests classify as 95.1 percent certain than those they classify as 94.9 percent certain—a practice that seems more superstitious than scientific." (P. 256 n. †). Sure, any rigid dividing line (a procedure that Fisher did not really use) is arbitrary, but rejecting a hypothesis in a classical statistical test at the 0.05 level does not imply a 95% certainty that this rejection is correct.

In transposing conditional probabilities in violation of both Bayesian and frequentist precepts, Silver is in good and plentiful company. As the pages on this blog reveal, theoretical physicists, epidemiologists, judges, lawyers, forensic scientists, journalists, and many other people make this mistake. E.g., The Probability that the Higgs Boson Has Been Discovered, July 6, 2012. Despite its general excellence in describing data-driven thinking, The Signal and the Noise would have benefited from a little more error-correcting code.


* Rather, Gunzelmann & Gluck (2004) discusses training in unspecified "mission-relevant skills." An "expert model is able to compare their actions against the optimal actions in the task situation" and "identify [trainee errors] and provide specific feedback about why the action was incorrect, what the correct action was, and what the students should do to correct their mistake." The expert model--and not the soldiers--"uses Bayes’ theorem to assess mastery learning based upon the history of success and failure on particular units of skill within the task." Ibid. According to the authors, this "Bayesian knowledge tracing approach" is inadequate because it "does not account for forgetting, and thus cannot provide predictions about skill retention." Ibid.

** Lichtenstein & Fischhoff's (1978) objective was "to help analysts to more accurately use numerical probabilities to indicate their degree of confidence in their decisions." They did not study military analysts, but instead recruited 12 individuals from their personal contacts. They had these trainees assess the probabilities of statements in the areas of geography, history, literature, science, and music. They measured how well calibrated their subjects were. (A well calibrated individual gives correct answers to x% of the questions for which he or she assesses the probability of the given answer to be x%.) The proportion of the subjects whose calibration improved after feedback was 72%. Ibid.


Walter Frick, Nate Silver on Finding a Mentor, Teaching Yourself Statistics, and Not Settling in Your Career, Harvard Business Review Blog Network, Sept. 24, 2013,

Christopher J. Gill, Lora Sabin & Christopher H. Schmid, Why Clinicians Are Natural Bayesians, 330 Brit. Med. J. 1080–83 (2005), available at

Glenn F. Gunzelmann & Kevin A. Gluck, Knowledge Tracing for Complex Training Applications: Beyond Bayesian Mastery Estimates, in Proceedings of the Thirteenth Conference on Behavior Representation in Modeling and Simulation 383-84 (2004), available at

Sarah Lichtenstein & Baruch Fischhoff, Training for Calibration, Army Research Institute Technical Report TR-78-A32, Nov. 1978, available at

Gary Marcus & Ernest Davis, What Nate Silver Gets Wrong, New Yorker, Jan. 25, 2013,

Tony Waldron, Palaeopathology (2008), excerpt available at