The Fallibility of Drug Sniffing Dogs

Radley Balko has a new article at Reason, The Mind of a Police Dog, discussing reasons why drug dogs are not as accurate as police and courts assume. It may not be the dog's fault:

The problem is our confusion about when dogs are picking up a scent and when they are responding to cues from their handlers.

....The problem is that a dog barking or sitting may be responding not to a smell but to his handler's hunch about a suspect's guilt. The reason we have a Fourth Amendment is precisely to prevent searches based on hunches.

Courts don't require warrants for K-9 searches, yet they conclude that a positive hit is probable cause for a search.

A recent Chicago Tribune study found the dogs are frequently wrong. More on the study here, and from Jacob Sullum, in A Drug-Sniffing Coin Would be Cheaper. Once again, the Fourth Amendment is going to the dogs.

< DEA Crackdown on Florida Pain Clinics | Wednesday Night Open Thread >
  • The Online Magazine with Liberal coverage of crime-related political and injustice news

  • Contribute To TalkLeft

  • Display: Sort:
    Devastating Arguement Against K-9 Searches (5.00 / 1) (#2)
    by john horse on Wed Feb 23, 2011 at 09:44:39 PM EST
    According to the study, dogs are accurate 27% to 44% of the time.  How can you base probable cause for a search on something so unreliable?  

    I suspect law enforcement has known for years how fallible K-9 searches were.  Just one of the dirty little secrets that they kept under their hat.

    "probable cause" (none / 0) (#10)
    by diogenes on Thu Feb 24, 2011 at 12:17:25 PM EST
    If a preponderance of the evidence is greater than fifty-one percent, then surely 27-44% represents probable cause.  If you searched random people based on "hunches" you wouldn't catch one in one hundred.  

    And I'm sure that (none / 0) (#11)
    by Zorba on Thu Feb 24, 2011 at 01:09:37 PM EST
    you have some scholarly link for your assumption that you can point us to, as opposed to just your gut feeling?  

    Here's a starter (none / 0) (#12)
    by jbindc on Thu Feb 24, 2011 at 01:21:58 PM EST
    It's for FISA warrants specifically (which have a lower threshhold than a police search), but they start with the definition of "probable cause" in general.



    "Probable cause" (none / 0) (#13)
    by Zorba on Thu Feb 24, 2011 at 01:36:19 PM EST
    in your link seems to be all over the place (and even in the cases where the courts found it to be appropriate, I do wonder what the Founding Fathers would have thought).  It certainly does seem that in FISA cases, as you said, the courts are more willing to give the doubt to the authorities (not that I necessarily agree with that, but then, I'm a hard-core Civil Libertarian and a long-time member of the ACLU).  I'm not convinced that this speaks to the constitutionality of the so-called "noses" and reactions of drug-sniffing dogs (which have shown to be less than 50% unreliable) being sufficient "probable cause."

    And for something more scholarly (none / 0) (#14)
    by jbindc on Thu Feb 24, 2011 at 01:36:30 PM EST
    From the December 2010 LAW AND CONTEMPORARY PROBLEMS (Duke University Law School)

    We do not know exactly what the phrase "probable cause" means, in strict numerical terms. We do, however, know what it does not mean: "probably." That is, probable cause does not--in the context of Fourth Amendment law mean that the police must have evidence sufficient to conclude that a suspect is
    probably guilty or that she probably has evidence of a crime hidden inside her home. It is, accordingly, perfectly consistent with the constitutional ban on unreasonable searches and seizures--under existing doctrine--to arrest or
    search a person on the basis of suspicion that does not rise to the level of a "preponderance" of the evidence. The arrestee's guilt (or the presence of evidence in a place to be searched) need not be "more likely than not."

    The Supreme Court has said that "`[t]he substance of all the definitions' of probable cause `is a reasonable ground for belief of guilt.' And this `means less than evidence which would justify condemnation' or conviction . . . . [I]t has come to mean more than bare suspicion . .. ." The Court has also said, in discussing post-arrest, probable-cause hearings, that "[probable cause] does not require the fine resolution of conflicting evidence that a reasonable-doubt or
    even a preponderance standard demands
    . . . ." Additionally, "only the probability, and not a prima facie showing, of criminal activity is the standard of probable cause . . . ." And finally, the probable-cause standard "does not demand any showing that such a belief be correct or more likely true than false." Though some of the cases are relatively old, the Court has not subsequently retreated from the position--however obliquely stated--that probable cause is something more than bare suspicion but something less than "more probable than not."

    Some may quarrel with the legitimacy of this standard and suggest that a preponderance of the evidence would be a more appropriate prerequisite to arrest. Even if one were to adopt a more stringent definition of "probable cause," however, it would nonetheless remain the case that the standard does not rule out--and can be said, in fact, to contemplate--that innocent people
    will regularly suffer the indignity and deprivation of an arrest for crimes of which they are completely innocent. This consequence is unavoidable,regardless of the standard, if searches are permissible at all. Indeed, I have elsewhere argued that the Fourth Amendment, in setting out "probable cause" as a limiting principle for searches and seizures, explicitly and inherently balances the privacy and liberty of innocent people against the also-significant
    goal of protection of the public from criminal predation. If it were otherwise, it would not be necessary to tolerate error--the law could simply bar all intrusive criminal investigation on the basis of anything less than proof beyond a reasonable doubt (or better, absolute certainty). Such a robust protection for privacy and liberty, however, would come at a great cost--the inability of law enforcement to act to detect and, perhaps even more importantly, prevent criminal behavior about which they do not already have all of the facts.

    The Fourth Amendment compromise thus means, necessarily, that police who investigate to the extent that they may, consistent with constitutional limits, will sometimes inflict frightening, humiliating, and unpleasant lawenforcement events--searches and seizures--on innocent people. If we assume that "probable cause" is as close to a preponderance of the evidence as possible, without actually rising to a preponderance, then the doctrinal standard
    contemplates that at least fifty percent of those lawfully searched and seized will be innocent and thus undeserving of any intrusion.

    Link (none / 0) (#15)
    by jbindc on Thu Feb 24, 2011 at 01:44:49 PM EST

    Note:  I'm not arguing about whether or not dogs used are a good idea or not, but just pointing out that "probable cause" is a standard even below that of "preponderance of the evidence".


    I wouldn't expect (none / 0) (#16)
    by Zorba on Thu Feb 24, 2011 at 07:05:48 PM EST
    the police to have to hold to a "preponderance of evidence" standard when searching or arresting someone, but I don't think that requiring a "more likely than not" standard would be unreasonable- that, at least, would be my preference.

    I know what you mean, but I had (5.00 / 1) (#3)
    by ruffian on Thu Feb 24, 2011 at 08:31:27 AM EST
    to giggle at this:
    It may not be the dog's fault:

    I'd say it most assuredly is not the dog's fault! He'd rather be doing other things.

    Deputizing dogs... (none / 0) (#7)
    by kdog on Thu Feb 24, 2011 at 09:34:21 AM EST
    too bad the practice isn't considered in violation of animal cruelty laws.

    Turning man's best friend into his adversary...if it ain't cruel, it certainly ain't too cool.


    The Problem is There are No... (5.00 / 1) (#4)
    by ScottW714 on Thu Feb 24, 2011 at 08:55:07 AM EST
    ... defined standards/metrics/courses for the dogs or the handlers.

    They train, house, feed, and care for the dogs almost entirely.  So one dog may receive adequate training, while others don't, yet in court they are viewed with the same reliability.

    I just saw a special on this, and a lot of the time the handlers actually assumes the costs of feeding the animals and housing usually means the handler's home.  I'll post the link, but there are so many problems it's amazing that any court in the land would rely on their identifications.

    The article also discusses this issue with bomb sniffing dogs, which IMO are a far more valuable tool that drug sniffing dogs.  

    I suspect this is fairly easy to keep under wraps because no one reports when the dogs come up empty, it's not very invasive and it only means the cop's intuition was wrong.  And when they are right, well it's pretty hard to argue the dog's accuracy after a kilo of blow is found in your trunk.  Regardless if the trainer signaled the dog to the trunk.

    It requires a great deal of time (5.00 / 0) (#5)
    by Militarytracy on Thu Feb 24, 2011 at 09:08:56 AM EST
    constant training, to keep such a dog sharp even after the best training.  I don't think that police departments want to fund it or provide it.  The dogs that the military uses and the dogs that are used in fire investigation spend their whole lives doing only one thing, that one job that they are expert in.  And their handlers live, eat, and breathe it too.  That is why when I see a K-9 marked unit go down the road I never think about the dogs having scent abilities.  In my mind, if a dog is riding around in car all day while an officer writes tickets and does routine things, I'm sorry but the dog is so distracted by all the daily activities and what he must do to fit in, his scent skills at that point are pretty nonexistent other than he smells something.  He smells lots of somethings.

    Why wouldn't they (5.00 / 0) (#9)
    by sj on Thu Feb 24, 2011 at 10:11:26 AM EST
    use a flawed methodology?

    there are so many problems it's amazing that any court in the land would rely on their identifications

    They've been using eyewitness identification for decades despite all the evidence that it is a flawed methodology.


    yes - I can see using the dogs as a tool (none / 0) (#8)
    by ruffian on Thu Feb 24, 2011 at 10:08:20 AM EST
    but using their reactions as probable cause for a search is just wrong. A good handler can train a dog to respond to any subtle signal and a court would never know.

    might as well use better technology (none / 0) (#1)
    by beowulf on Wed Feb 23, 2011 at 08:59:29 PM EST
    "Pigs have a more acute sense of smell than dogs.
    An Israeli animal handler trains pigs to sniff out landmines and explosives."

    the issue of a dog responding to a "handler's hunch" is a very good point.  Dogs are very intuitive and if a K-9 senses its handler tensing up when dealing with a particular suspect, it could react to that and not what it smells.

    Dogs are intuitive, (none / 0) (#6)
    by Zorba on Thu Feb 24, 2011 at 09:09:39 AM EST
    but an animal needn't be a dog to pick up the cues of the owner/trainer.  You've probably heard the story of Clever Hans.  And that was over a century ago.  The handler may not even be aware that he's giving the dog cues.  (Although some of them may be, and do it deliberately- we'll probably never know.)

    The Clever Hans effect: (none / 0) (#17)
    by Mr Natural on Fri Feb 25, 2011 at 04:43:35 AM EST
    Named for a horse who wasn't as clever as advertised.  In 1907, Clever Hans was proven to be following cues from his owner, who innocently believed in the horse's intellectual acuity.  

    Oops! This was mentioned in the original article. (none / 0) (#18)
    by Mr Natural on Fri Feb 25, 2011 at 04:49:35 AM EST