Case Probability vs. Class Probability
The stories and statistics that draw outrage tend to share two common elements: They involve a search for drugs and the prospect of asset forfeiture. These types of investigations have led police from the solid ground of "case probability" to the shifting sands of "class probability" in their quest for probable cause. Once police are operating on the basis of class probability, there is a strong claim that certain groups of people are being denied equal protection under the law.
Case probability describes situations where we comprehend some factors relevant to a particular event, but not all such factors. It is used when a doctor tells a patient, "Given your lifestyle, you'll probably be dead in five years." Class probability refers to situations where we know enough about a class of events to describe it using statistics, but nothing about a particular event other than the fact that it belongs to the class in question. Class probability is being used when an insurance company estimates that a man who is 40 today will probably live to be, on average, about 80. The insurance company is not making any statement about the particular circumstances of any particular man, but merely generalizing about the class of 40-year-old men.
This distinction helps us to differentiate two ways of using information about race or ethnicity in a police investigation. As an example of the first type, employing case probability, consider a mugging victim who has told the police that her mugger was a young Asian man. Here, it is quite understandable that the group of suspects investigated will not "look like America." There is no sense in forcing the police to drag in proportional numbers of whites, blacks, women, and so on, proving that they have interrogated a representative population sample of their city, before they can arrest an Asian fellow. No, their investigation should clearly focus on young Asian men.
It's not at all impossible that a prevalence of some type of criminal activity in some ethnic group will lead to many investigations that focus on members of that group. As long as this is based on evidence gathered from particular crimes, there is nothing untoward here. If it turns out, for instance, that Bulgarians are especially numerous among purse-snatchers in some city, then a summary of police interrogations might discover evidence of "Bulgarian profiling" in the investigation of purse-snatching. But this may be a statistical mirage if it turns out that no one in the police force set out to focus on Bulgarians as potential purse-snatchers. The emergent result is an unintended outcome of policemen following an entirely valid principle of crime investigation: Concentrate on suspects who fit the description you have of the suspect.
But when we turn our attention to the type of racial profiling that occurred on the highways of Maryland and New Jersey, or that is described in the Forest Service memo, we find a very different phenomenon, one where investigations proceeded on the basis of class probability. Here, before having evidence of a particular crime, police set out intending to investigate a high proportion of people of some particular race, ethnic group, age group, or so on. Their only justification is that by doing so, they increase their chances of discovering some crimes.
Additionally, there is a fundamental difference between the type of crime, such as the mugging example above, that is usually investigated by gathering evidence about a known crime, and narrowing the search based on such evidence, and the type investigated by looking in as many places as possible to see if one can find a crime. The first type of crime generally has a victim, and the police are aware of a specific crime that has been committed. The crime is brought to the attention of the police by a complainant, even if the complainant is a corpse.
George Will, in his defense of current police practice, points out: "Police have intelligence that in the Northeast drug-shipping corridor many traffickers are Jamaicans favoring Nissan Pathfinders." This is quite a different situation than having intelligence that a particular Jamaican robbed a store and escaped in a Pathfinder. If you are a law-abiding Jamaican who by chance owns a Pathfinder, you frequently will find yourself under police surveillance, even though the police have no evidence about any particular crime involving any particular Jamaican in a Pathfinder.
We could not have any effective law enforcement without allowing some scope for case probability. If your twin brother robs a bank in your hometown, it does not seem to be a civil rights issue if the police stop you on the street for questioning. When the police discover their mistake, they should apologize and make you whole for any damages you have suffered. Such an event, while unfortunate, is simply a byproduct of attempting to enforce laws in a world of error-prone human beings possessing less-than-perfect knowledge. It will be a rare event in law-abiding citizens' lives, and it is highly unlikely that such people will come to feel that they are being targeted.
However, the use of class probability in police investigations is correctly regarded with extreme suspicion, as it violates a basic principle of justice: The legal system should treat all citizens equally, until there is specific, credible evidence that they have committed a crime. In the cases we've been discussing, we can say that the odds that any particular young black or Hispanic man will be hassled by the police are much higher than for a white man who, aside from his race, is demographically indistinguishable from him. These minority men, no matter how law-abiding they are, know that they will be investigated by the police significantly more often than other citizens who are not members of their racial group. The social cost of the alienation produced by this situation cannot, of course, be measured, but common sense tells us that it must be great.
As important, in the majority of "crimes" that such stops discover, there is no third party whose rights have been violated, who can step forward and bring the crime to the attention of the police. To discover victimless crimes, investigators must become intrusive and simply poke around wherever they can, trying to see if they can uncover such a crime. When someone drives a few pounds of marijuana up I-95 from seller to buyer, who will come forward and complain? It's not merely that, as in the cases of robbery or murder, the perpetrator may try to hide his identity, but that the "crime" has no victim.
Drug War Profiling Practices
Both statistical studies and anecdotal evidence support the view that drug crimes are the almost exclusive focus of investigation in racial profiling cases. Hence, The New York Times reported in February that, "The New Jersey State Police said last week that the number of drug arrests on the Garden State Parkway and the New Jersey Turnpike fell last year, after the department came under scrutiny for racial profiling. The number of drug charges resulting from stops on the turnpike were 370 last year, compared with 494 drug charges in 1999. There were 1,269 charges filed in 1998. On the parkway, troopers reported 350 drug charges last year compared with 783 in 1999 and 1,279 in 1998."
The Record, a Bergen, New Jersey, newspaper, obtained state police documents last fall. One document, used for training, teaches troopers to zero in on minorities when scanning state roadways for possible drug traffickers. Titled "Occupant Identifiers for a Possible Drug Courier," the document instructs troopers to look out for "Colombian males, Hispanic males, Hispanic and a black male together, Hispanic male and female posing as a couple." (One's mind boggles at how the police are able to detect that two Hispanics are "posing" as a couple as they zip by at 60 miles per hour.) The undated document also teaches troopers how to use supposed traffic violations, such as "speeding" and "failure to drive within a single lane," as a pretext to pull over suspected drug couriers.
If police have a goal of maximizing drug arrests, they may indeed find that they can achieve this most easily by focusing on minorities. Blacks on I-95 in Maryland, for instance, had a significantly higher initial propensity to carry drugs in the car than did whites. "Racial Bias in Motor Vehicle Searches: Theory and Evidence," a 1999 study by University of Pennsylvania professors John Knowles, Nicola Persico, and Petra Todd, shows that despite the fact that blacks were stopped three-and-a-half times more than whites, they were as likely to be carrying drugs. But this doesn't mean their propensity to carry is the same. If we assume that the high likelihood of being stopped reduces some blacks' willingness to carry drugs, then if not for the stops, they would have been carrying proportionally much more than whites. The Penn professors conclude they are displaying what they call "statistical discrimination" (i.e., the police are operating on the basis of class probability) rather than racial prejudice. Perhaps more to the point, they conclude that the police are primarily motivated by a desire to maximize drug arrests.
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Jagwar|1.23.10 @ 5:54PM|#
You mother fucks always discriminate us and you will soon see
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HM|2.16.10 @ 1:14AM|#
This is not fair. Each personhas his or her personality,do not judge from the race. This is streotype.
Mubaraka |2.16.10 @ 1:14AM|#
I think tgis is happened a lot in America beacuse tgey think that black people are bad. although, i see that is wrong beaucse the police officr must check before give the judgment and see why this man was driving very fast ( the reason)
Mohamed Salem |2.16.10 @ 1:15AM|#
They should respect and deal with all of them fair even they are from diffrent race.
F. A|2.16.10 @ 1:16AM|#
The police should deal with all people equally. Because, differences dealing between people causes many problem in the country.
ECAE|2.16.10 @ 1:17AM|#
This article have many difficult vocabulary, so not everyone can read it.
The reader will find some difficulties to read this article, when they will start reading they will face issues that will change their mind in complete reading this article.
If the article was written in a simple vocabulary it will ba great.
Afari Alernast|2.16.10 @ 1:17AM|#
It is wrong way or stopping the pepole beacuse we should not gudge the peopole by there color. And should thier police to del with pepole equal =)
Jood|2.16.10 @ 1:18AM|#
Police job request to respect each one and deal with all in same way.
Everyone are same that dosen't deponds on the cultuers or the countries all we are same.
Nuha|2.16.10 @ 1:19AM|#
The policemen should not judge from the the first look. The man who drives like a drug trader could look cute, but they hide what they feel.
F. A.|2.16.10 @ 4:08AM|#
all countries have racial profiling but with some education people are trying to be more open.
sh|2.16.10 @ 4:14AM|#
All people are equal and police must respect all. there is no different between people in their race
sho sho|2.16.10 @ 4:14AM|#
It is not fair to discriminate people by their faces or their skin because all of us are human and we have different faces and different skin. SO, we should treat people equally.
Eiman|2.16.10 @ 4:19AM|#
The personality of a person is not related to the external appearence. Sometimes people are surprising and not what we expect. So, this is not fair.
Super Junior |2.16.10 @ 4:20AM|#
Our Islam saves our dignity by prohibiting this issue .. that why i proud i am Muslim =D
thanks Allah
Dong Hae
AA|2.16.10 @ 4:20AM|#
IN MY OPINION THERE AER NO DIIFRENT BETWEEN WHITE AND BLACK PEOPLE.DIFFRENCE DEALING CAUSES MANY PROBLEMS IN THE COUNTRY.COLOR IS NOT THE BASIC THING TO JUDGE THEM BECAUSE EVRYONE HAS THE SAME RULES IN THE COUNTY AND ALSO THEY HAS OPPERUNITY TO DO THE SAME THINGS.
Al muharrami *-*|2.16.10 @ 4:20AM|#
I think they should make a balnce between the white and black person.
Also, they must deal with them equally and both of them are same, same and same^^
We must judge the person from her or his work and effort, NOT from the race.
h|3.2.10 @ 10:21PM|#
Is everyone on here illiterate, foreign, or 7 years old? Look at the grammar mistakes. There is spell check on the comment space you know....
First off, this is a matter of U.S. affairs, not foreign affairs.
Racial profiling helps aid in preventing crimes and I am sure these radical stories like stated in the begging of the article are not "daily occurrences on our nation's highways".
To the author: Stop being so sensitive and radical. Those who used profiling correctly actually used logic, not race. Race has a factor in this logic and therefore some feel it is a racial attack.
|9.29.10 @ 7:18PM|#
Good job calling out everyone of spell check "h". However, spell check does not fix all literate issues. Such as when you wanted to say beginning, but rather said "begging".
To the rest of your comment their are several studies that have been preformed that show when officers do not use race as a means to determine whether or not someone is a suspect and instead use reasons they would have to use if we were all one same color such as behavior, their findings of drugs and related materials were 300% higher. Not to mention the fact that if allowed to act mainly off race several whites like myself would be able to be overlooked even if they are carrying drugs or even perhaps going to blow up a building. Timothy McVeigh almost alluded police due to the fact that the were acting on a profile given to them that depicted the man as that of Arab ethnicity.
h|3.2.10 @ 10:27PM|#
[Quoted from:
Jagwar|1.23.10 @ 5:54PM|#
You mother fucks always discriminate us and you will soon see]
Threats....Good job in proving my point. Nice hostility.
nfl jerseys|11.14.10 @ 8:28PM|#
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