Amped Up Over Tasers: When Technical Details Don't Mix

Adoption of the electrical neuromuscular incapacitation device commonly known as the "Taser" is a contentious issue in law enforcement policy. As with many contemporary issues, the adoption and deployment of the Taser appears to incite a spirited public debate that is, in actuality, not so much a debate as a vicious clash of two different sets of vague and incommensurable intuitions. As should not be surprising, this quagmire of ill-formed but irreconcilable feelings is even more severely exacerbated whenever the works of science and late technology are involved.

In recent local news, an action group calling itself "People for a Taser-Free Columbia" hosted a public discussion on the police department's issuance of Tasers to beat officers. At that event, opponents raised frequent objection to the Taser: it subjects its victims to an electrical potential of 50,000 volts. This quantity, opponents contend, is manifestly unsafe, whence the Taser's status as a non-lethal weapon is questionable. The Columbia Daily Tribune reports that a certain city councilman dismissed this objection by noting that "it's not the voltage that matters, it's the amperage." Exchanges such as these have become typical in American civic discourse: one side glibly cites what appears to be a fact, and the other side, without considering any particular features of the problem, dismisses that fact as irrelevant. Because such exchanges have become typical it is easy to mistake them for serious policy debate, when in fact they are little more than hysterics and posturing on either side. This recent exchange by Taser opponents and the city councilman is a striking illustration of how much worse matters become when technical information is involved, and is often unwittingly used to perpetuate an unproductive argument.

A closer examination reveals how little the participants in this debate are actually saying. (Sadly, it's worth even less than the few sentences we've given it here.) Let's first address the councilman's inane rebuttal.

Electrical current is commonly measured in amperes. On this definition, the councilman seems to assert that the voltage figure quoted by opponents is irrelevant on the basis that it is the quantity of electrical current that actually determines the magnitude of injury. The councilman's objection superficially appears erudite: he correctly distinguishes between current, which measures the rate at which electrical charge flows through a medium, versus voltage, which is a measure of potential energy. Opponents, however, are clearly objecting to the Taser on the basis that its sheer energy output seems to be frighteningly high. Does the councilman's remark actually address the spirit of this concern? According to Ohm's Law, a basic physical principle familiar to anyone who has ever taken a college physics course,

electrical current = electrical potential / electrical resistance

which means in particular that current, and thus 'amperage', is proportional to voltage. Thus a small voltage will produce a small current when applied to a given conductor (e.g. a human subject), and a very large voltage will produce a very large current when applied to the same conductor. The number of amperes experienced by a person shot with a Taser dart thus depends upon the number of volts of electrical potential generated by the device. What the councilman seems to be saying is: "It doesn't matter how many volts the suspect is subjected to, as long as he doesn't suffer too many amps." In light of simple physical laws, such an argument makes no sense. Moreover, it does nothing to address generic fears that Thomas A. Swift's Electric Rifle shoots out a quantity of electricity that is simply too large.

It is possible the councilman actually meant something else by his objection, but I cannot think of any other sensible (or favorable) way to construe the remark. It is also worth noting that the councilman's remark is similar to an aphorism oft quoted in the electrician's trade. In the context of creating an electrical current, an electrician or engineer certainly is concerned with the problem of creating a current using as little voltage as possible, but this is quite a different concern than determining how much current can be applied to a human being without causing injury or death. Let this be a lesson about the danger of repeating aphorisms without clearly understanding their meaning and application. Be careful not to use pre-packaged phrases to cover up a lack of understanding.

The councilman's technical flub was only made worse when the Deputy Chief of Police asserted, according to the same Tribune article, that the Taser induces a current that is "much less than a standard wall socket's output." Considering that, in the United States, electricity is transmitted to homes at 120 volts, it is impossible that a correctly functioning wall outlet could induce a current greater than the peak current produced by a successful Taser deployment. According to Taser International Inc., the device's manufacturer, the TASER X26 delivers a maximum effective voltage of 1200 V across the body of the subject. All things being equal, Ohm's Law entails that the peak current delivered by a relatively low-voltage taser is at least ten times what a wall outlet could deliver.

This flub, however, leads into one of the subtle difficulties of citing figures: there are many to choose from, and it often matters which you choose. One should note that I said the X26 delivers a peak voltage of 1200 V; the one-second baseline average reported by the manufacturer is only 0.76 volts. There is probably a substantial and pertinent debate to be had on whether the peak or the average current output is more meaningful to the issue of the Taser's ability to do mortal harm, or how long a peak must be in order to be physiologically relevant. However, none of these issues were raised by any participants that I am aware of, nor is there any evidence that the Deputy Chief took these matters into account. One could blame the genre of news reporting: there is only so much space, and reporters favor simple questions with short answers. Moreover, the Deputy Chief is a peace officer, not an electrical engineer; he may have little or no knowledge of the Taser's technical details, beyond those necessary to its operation, and is mostly likely citing the nearest available figure.

Nonetheless, newspapers need to be able report news concisely, and police officers need to be able to do their jobs without worrying about a lot of scientific ephemera. What could have been done differently? The reporter could have troubled his or her self to formulate a somewhat more specific question -- and to follow up on fact-checking the answer. The Deputy Chief, for his part, could have given a more generic expression of his confidence in the device's safety. This would sufficiently express his position without giving the misleading and all too often conjured appearance that "this is all very scientific and things are completely under control." Don't cite specifics unless you are certain of specifics.

(Specifically Deputy Chief claimed the Taser's current output to be 0.014 amperes, without specifying this as average or a peak, or giving a source. I could not locate this figure on the manufacturer's website.)

Now, on to the question of the Taser opponents. The attentive reader may have noted that the peak voltage I cited above for the TASER X26 (1200 V) is substantially below the sensational 50,000 V figure. This is because, while the electrical circuitry of the Taser does in fact produce an internal potential of 50,000 V, this voltage is not the voltage applied to the body of a person shocked by a Taser. According to a Taser International fact sheet the Taser's effectiveness is partially due to its ability to administer a shock even in the case that the terminal probes do not make skin contact with a subject, e.g. in the instance that the probes are embedded in exterior clothing and do not reach the skin. The Taser accomplishes this by steadily increasing its internal voltage, up to 50,000 V, until the potential difference is sufficient to produce an electrical arc from the probes to the body of the subject. Much of the current produced by the 50,000 V potential difference, however, is lost in the process of "jumping" across the gap between the probes and the body of the subject. As soon as the potential difference built up within the device is released (by shocking the unfortunate person on the other end), the voltage rapidly drops. The extra voltage within the Taser is thus built up only far enough to overcome any electrical resistance on the probe end and thus to produce a current sufficient to subdue the human subject. (The basic idea at work here is also very succinctly described by Ohm's law.) What this means it that no person subjected to a shock from a correctly functioning Taser experiences anything close to 50,000 volts.

(That is not to say, however, that their experience is a pleasant one.)

Though I respect opponents' interest in protecting the public safety, they would know that the figure they so often quote is actually not pertinent if they had troubled themselves to learn about the issue they're debating. Throwing out a figure as an emotional artifact ("Look how big it is!") fails both rational discourse and impassioned elqoeunce. When facts in general, and numbers in particular, are used this way, it is usually results either from someone's lazy skimming of the available information for the first apparently supporting technical fact, or from the widespread repeating of such a carelessly disjointed fact. The end product is a clumsy admixture of fevered pleading and rote recital. The fact that Taser opponents often cite a technical fact of no relevance to their legitimate concerns diminishes their apparent gravity and opens the door to glib dismissals like the councilman's 'amperage' remark.

It would be nice if policy decisions were made the same way that a scientific question is studied or an engineering problem is solved: a collection of experts would assemble, collect and analyze as much data as possible, render a decision or propose a course of action, and publish the findings for public scrutiny. Even if such a system of governance were possible, however, I think it would be at best naive to expect it at this stage in history. Moreover, human societies have to take into account human passions; these can't be swept under the rug if any kind of peace or social harmony is to be maintained. A mode of governance more scientific than those in existence today would still have to account first for the hopes and fears of the governed, else it would be nothing but a brutal, mechanical autocracy. Putting aside dreams of later and elsewhere, what could be done differently right here and right now?

The episode at People for a Taser-Free Columbia's forum is problematic because both parties are clearly talking past one another, and using misconstrued technical details to do so. The effective output of the Taser and its short- and long-term physiological effects are essential points to understand and take into account. However, neither party seems to be seriously considering these issues, so much as cherry-picking bits and pieces to suit their existing biases. Both parties, however, have valid concerns that do not necessarily lie within the bounds of engineering details or known laws of electricity. Police serve a useful and necessary function any society, but citizens do have a legitimate interest in checking police powers and in dictating what is and what is not acceptable police action. This is a natural source of tension. The idea of a new kind of weapon is viscerally scary to any normal human being, and it is natural that some citizens would be concerned that the police, to whom they have granted a substantial measure of power, use these new weapons carefully and responsibly. On the other hand, early evidence suggests the Taser is a highly effective, non-lethal means for officers to subdue aggressive persons, with the promise to greatly reduce the incidence of serious injury to either police or citizens during arrest scenarios. These are two points of view that surely can be brought to some satisfactory reconciliation; Taser opponents surely would not want to see a greater number of suspects or police officers harmed during arrests, nor would Taser proponents want to see the police issued a weapon that posed unacceptable dangers to public.

To emphasize this last point, consider that in the most controversial Taser episodes in recent history (some of which are also local) are controversial not because an electrical neuromuscular incapacitator was deployed, but because it was deployed under highly questionable circumstances. In one sensationally publicized episode last year, Columbia police used a Taser on a man threatening to jump from the I-70 overpass at Providence Road, causing him to fall 15 feet to the highway median below. A Taser was used in spite of the fact that the man in question threatened nothing more than suicide, in spite of the fact that he was only passively uncooperative in his refusal to move himself to safety, and in spite of the fact that the officer's action quite foreseeably caused the man to fall from this perch, thus causing the very injuries police had sought to prevent the man from visiting on himself. In another episode on August 28 of last year, police in Moberly, Missouri used a Taser against one Stanley Harlan during a routine traffic stop; Mr. Harlan died shortly thereafter. The event has come under scrutiny because Mr. Harlan was Tased at once while lying on the ground. The city of Moberly has since agreed to pay the Harlan family $2.4 million.

Episodes such as these underscore the legitimacy opponents' concerns that the new weapon may be irresponsibly or recklessly deployed. At the same time, it is clear that the harm in these episodes was not essential to the Taser itself, but resulted from improper police conduct, which, it can be convincingly argued, could be remediated by better training and more stringent department policies on Taser use. By contrast, these salient points are lost behind shrill assertions about tens of thousands of volts, or the supercilious amperes that somehow matter more.

In closing, I would like to point out that I have assumed that Taser International Inc.'s technical data is all complete and correct, and that I have no reason to believe otherwise. However, this is a crucial assumption. The skeptical citizen should remember that every manufacturer has a large material interest in the perceived safety of their product and so is not necessarily an impartial judge of potential dangers said product may pose to the public.

The lesson in all of this is that we would do well to find a better way to express and legitimize the seemingly vague and unquantifiable hopes and fears from which our views originate. It's more communicative to say, "I'm afraid the police," than, "According to my calculations, the Gizmotron 3000 shoots out too many volts!" We need to be willing to acknowledge that we're human beings, with human hopes and human fears that need to be openly acknowledged and should be respected without qualification. At the same time, we also need to consider hard facts and well analyzed data in making decisions, being careful not to misuse them to give trappings of legitimacy to arguments that more emotional than rational. It's ultimately hopes and fears that bring us together as human beings; we should use the facts to harmonize rather than to obfuscate our deeper motives.