8 ms·

How Likely Is Someone Accused of Assault by Multiple People to Be Innocent?

43 points by svtrent 12y ago

Alex3917 12y ago
> The intuition that, “if you are accused of assault by multiple people, you’re probably guilty” is often accurate. Importantly, even if you were to choose settings where someone who has been accused once is more likely than not to be innocent, the probability of innocence often drops dramatically if they have been accused twice. This doesn't account for whether or not the accusations are independent of one another, which in this case most were not.
- statistician409 12y ago
  (I'm the author of the post) the fact that accusations may not be independent is of course important (although I'd question the aptness of the above commenter's comparison to witch trials); I'd welcome your suggestions for incorporating correlations into the model. This is one of the reasons the tool discussed in the NYT's article could be powerful -- because it allows us to be more confident that accusations were levied independently, since people submit to the tool without knowing about other accusers.
  - logicallee 12y ago
    The comparison with witch trials is simple. People can be totally independent, and not know each other, and independently conclude that you're a witch. Why would they do this? Obviously due to some factor about you. The mistake you make is using Occam's razor to conclude that that factor is "being a witch". The other poster used the example of witches because we all know there is no such thing. There is 0% chance of someone being a witch, whom nobody has ever so much as suspected of being a witch. But there is also 0% of someone being a witch, about whom dozens of totally independent people, in different locations, throughout the person's life and career, have independently come to the firm and undeniable conclusion that they are a witch. This is why this was the example that was used.
    - darkhorn 12y ago
      Everyone says that [put some religion here] is true. All these people can't be wrong, can they be? Therefore this religion is true. Applies not only to religion but also to heating home, sickness, astrology, cutting penices of children etc.
      - logicallee 12y ago
        Not bad :) Author should post "How likely is someone to be the son of God based on number of disciples?" and we can see where 12 fits in.
  - lectrick 12y ago
    You are not accounting for a few typical problems with these cases. 1) Eyewitness testimony ("personal accounts done a certain time after the event in question") is disappointingly terrible. http://www.scientificamerican.com/article/do-the-eyes-have-it/ http://www.scientificamerican.com/article/do-the-eyes-have-i... 2) The accuracy of human memory is disappointingly terrible. http://www.theatlantic.com/health/archive/2013/11/how-many-of-your-memories-are-fake/281558/ http://www.theatlantic.com/health/archive/2013/11/how-many-o... ... Especially under stress/duress/emotionally-charged events. https://en.wikipedia.org/wiki/Effects_of_stress_on_memory https://en.wikipedia.org/wiki/Effects_of_stress_on_memory Lastly, regarding the anonymous reporting tool cited in the NYTimes article- that is no different from an anonymous witchcraft reporting tool. Any single individual who accrues too much community ire (whether deserved or not) can get anonymously accused of something (and at minimum, publicly humiliated or reputation-damaged) by a collusive group of individuals (who can act with complete impunity due to anonymity). It is for this reason that I believe, difficult as it is to do, that all accusers should be known... unless we also allow anonymity to the accused while they fight off the accusations! A little bit more controversially (and I freely admit this may be ENTIRELY up for debate, YMMV), there may exist a false-accusation bandwagon effect due to the economic forces at play https://omegavirginrevolt.wordpress.com/2014/11/23/the-false-accusation-bandwagon-effect/ https://omegavirginrevolt.wordpress.com/2014/11/23/the-false... Essentially, each new woman who steps forward and does not file a criminal suit but a civil one makes it more likely that (for example) Cosby's liability insurer will force him to pay out to alleged victims regardless of actual guilt. In addition, the accuser, who is likely someone that the "fame" spotlight has left in the past, can enjoy some more time under it. You fail to account for the additional financial/fame ("perverse") incentive of joining a bandwagon in this regard, especially when the accused is a wealthy individual. I sincerely hope that the above does not come off as anti-victim, misogynist, or otherwise. I just think we need to remember the lessons from the Witchcraft Era as well as from psychology research of the past few years.
  - lotharbot 12y ago
    > "people submit to the tool without knowing about other accusers" Not necessarily. People can conspire to submit multiple accusations to the tool against the same person. Even without actual conspiracy, someone who is a target for other reasons could have multiple false accusations independently levied against them. Example: I have a friend who runs a religious ministry for ex-members-of-another-religion. This draws the ire of current-members-of-the-other-religion, and leads to a lot of things they post being flagged as abusive (even things like photographs of themselves.) In some cases, it's clear that there's a group conspiring -- something posted years ago will get flagged multiple times over the course of a day (FB once investigated and located a private group that was being used to coordinate mass-flagging efforts.) In other cases, it's just the most recent thing they posted, likely being independently flagged.
  - jamessb 12y ago
    Perhaps a better example of how a naive assumption of statistical independence has led to a severe miscarriage of justice is provided by the case of Sally Clark: https://en.wikipedia.org/wiki/Sally_Clark https://en.wikipedia.org/wiki/Sally_Clark I would be extremely wary of your claim that "multiple accusations enable us to get enough evidence to convict even in parameter regimes where a single accusation is never enough" (https://www.dropbox.com/sh/drrvcd5zzqclhbt/AACdWnx_wlfwnUoYFme9UgX9a/exercises_with_binomial_posterior_probabilities.pdf?dl=0 https://www.dropbox.com/sh/drrvcd5zzqclhbt/AACdWnx_wlfwnUoYF...).
darkhorn 12y ago
http://m.liveleak.com/view?i=db6_1370665965&comments=1 http://m.liveleak.com/view?i=db6_1370665965&comments=1
pekk 12y ago
Some centuries ago, there were periods when many people would get accused of consorting with the devil, and multiple witnesses would be brought forward to substantiate this, and many people were burned as a result. That's not just a problem of ancient superstition; as recently as the 90s, a number of people were convicted of Satanic Ritual Abuse, with multiple witnesses, and some of the real victims (often women working in places like daycare centers) have been in jail for decades on the basis of clearly unbelievable and coached testimony. Whenever one of these periods occurs, it's not a one-off act by some individual, nor even a matter of any specific religion. It's a clear indication that the justice system has been fundamentally compromised in the way it treats evidence and renders a final judgement. This article might have good intentions, but its method could be applied to witchcraft or Satanic Ritual Abuse, and obtain the same kinds of conclusions: If you're accused of witchcraft by multiple people, you're probably guilty. This is still mostly true if we don't believe that witches are a separate kind of people. Increasing our certainty that witches are witches is even good for the people who are accused of being witches. Counting up the number of accusations is clearly a wrong standard for determining that someone is guilty. The available evidence in each case matters, and accusations are not necessarily independent. The general presumption of innocence until proven guilty is still necessary and still applies to rape as to other crimes.
- jmount 12y ago
  I agree. A large count at best proves non-independence (or contamination). It really doesn't address if the contamination is a guilty party, a smear campaign or self-correlating accusations. The original article gave too much credence to the possibility of calculation solving this by even trying to work things as far as it did.
  - Retra 12y ago
    That was my first thought on reading the title: a million accusations is no better than one unless you can prove they are independent.
- philwelch 12y ago
  The difference being that witchcraft and satanism were moral panics that never actually happened to anyone, and rape is something that actually happens to real people fairly often.
dahart 12y ago
> But how can we combine multiple accusations of assault, given that survivors are usually unaware of each other and often reluctant to come forward? I see the other comments pointing at this potential problem as well, but I'll phrase it as a question - since the article opens with a reference to Bill Cosby, is it even valid to combine multiple accusations of assault when the accusers are aware of each other, possibly through media exposure, and may have come forward as a result? And while there is a (perhaps unsurprising?) correlation between independent accusations and probability of guilt, how can this statistical approach be responsibly used, and should it, and what for? Assault is awful and I'm sure the majority of assaults with even one accuser is (or should be) straightforward), but it seems like there are other uncontrolled possibilities here besides the independence of accusations, like whether the accuser and accused know each other.
- kaitai 12y ago
  One way to deal with this is discussed in the article -- if details of reports are not widely publicized (often the case), then details of reports/allegations can be compared. In many cases, as noted in the post, methods are consistent. You could use some Bayesian analysis to figure out the probability that independent reports would come up with the same details.
jeffdavis 12y ago
This article is reckless. The author throws out a mathematical model regarding a very sensitive subject with no evidence that the model reflects reality. In effect, it just gives a mathematical veneer to the author's guesses. Similar to how wearing a lab coat while stating your opinion makes it seem scientific. (The most obvious issue is non-independence, but there are plenty of other problems.)
- skj 12y ago
  Exactly correct. It was more or less, "Given this model, my assumptions are correct!", completely missing the point that the model was the assumption itself.
crazypyro 12y ago
Is there any consideration taken for the fact that public figures, like celebrities, present a larger target, based on their wealth and fame? I'd imagine that would make a difference when compared with a regular person who is not in the public spotlight or doesn't have a large estate. Does this "intuitive thought" actually represent real world events?
- kaitai 12y ago
  Take a look at actual accusations of celebrities. Because of their wealth and fame, they are really good at sweeping these accusations under the rug. The first really public allegation against Cosby, for instance, was made public in 2002. Since it took until 2014 for anyone to care, it seems doubtful that the wealth and fame of celebs makes them "better" targets. It would be really interesting for someone to actually pull lists of famous celebrities from the last few decades (from mentions in media, for instance), look at rape accusations, and classify results. I don't know how you could compare to "regular" guys as most non-famous people don't make the news even if accused of rape, but a comparison of conviction rates could be illuminating.
Xcelerate 12y ago
My issue is more with smear campaigns. Leave the concern of guilt or innocence to the justice system. For every 100 people that are "probably" guilty on the basis of hearsay, how many innocent ones have had their reputation irreversibly ruined by widespread internet witch-hunts? If these people would focus their time and energy on actually coming up with solutions to the problems they're complaining about in their generality rather than targeting specific individuals (for instance, solving the problem of performance enhancing drugs in cycling vs creating a media sensation about Lance Armstrong), I think society would be much better off.
jeffdavis 12y ago
"the rate of false accusations is low" I didn't read the study, but how could anyone know this? I suppose you could assume that a conviction means that the accusation is true, and that exoneration means that accusation is false, but there are a lot of cases where it's not known one way or another. I would be surprised if 90%+ of accusations result in a conviction, so the study must be assuming that any accusation is true if the accused is not exonerated. There are also other, like if one party believes an assault took place and the other does not, or if the accusation is true but the perpetrator is misidentified. Please correct me if I'm wrong, but my guess is that the statement above (alone, out of context) is not well supported by evidence.
- glenra 12y ago
  You're correct, the rate of false accusations might be quite high. The "2-8%" stat given in OP really should be "2-10%" - advocates somehow tend to lose track of a couple studies that came out on the high end - but even that number range is only the percentage of rape accusations that were brought to the police which were deemed demonstrably false. For instance: the alleged victim reported it to the cops but later recanted or changed their story so much that it couldn't be trusted, or the facts on the ground made the story as stated impossible. Advocates are correct to note that this "2-10%" includes some mistakes - true rape victims might be very confused in their testimony or might recant because they get frustrated with the justice system - but it still should probably be regarded as a lower bound on the actual number of false accusations, as it's a subset of the full total. False accusations that wouldn't show up in this measurable "2-10%" include (a) those in which the accusation is plausible, consistent and the accuser does not recant, (b) false accusations that aren't ever brought to the police.
  - rayiner 12y ago
    If we're not going to count false accusations that don't carry the threat of jail time, we should also look at cases where there was a rape but nothing was taken to the police.
  - clay_to_n 12y ago
    Are you sure this can be considered a "lower bound"? The amount of people who were raped and never went to the police could be much higher than the amount of people who lied to the police about being raped.
deleted 12y ago
[deleted]
darkhorn 12y ago
Not realated with statistics but this is how females think. This is a few years old real story I've heard, from Austria. There is some kind of part like graduation or something. A guy with his new girlfriend starts to make out. Before they start to make sex the guy asks to the girl her age. She replies that she is 16 or something like that. Then the fuys says that it is not approppriate and leaves her. Then the girl says to her friends that she was sexually abused... That he leaved her etc... Hello....????!!!
- ceejayoz 12y ago
  I'm glad we can determine "how females think" from a hearsay-based anecdote for which significant details are noted as "or something".
  - darkhorn 12y ago
    Similar one http://www.gazetesok.com/yazi/alkol-varsa-tecavuz-sayilmaz_219814 http://www.gazetesok.com/yazi/alkol-varsa-tecavuz-sayilmaz_2...
grandalf 12y ago
What about the probability of someone who has been accused multiple times to also draw false accusations? True ones? What about the substantially different personal cost of making an immediate accusation vs a delayed one? The same applies to someone like Snowden who could have waited until he was in his 70s before blowing the whistle.
upside 12y ago
The author starts off with a Bill Cosby example, front and center, then continues to develop a stat model while acknowledging an inability to account for incidentals, while never mentioning that Bill Cosby is more than likely to have a significant number of incidentals.... Like, tonnes of money and hangin' out at playboy mansions where shady-ness pervades. Back in the day, pre-blogging, when journalism was actually a profession, journalists were taught to avoid this kind of set up. Now it's everywhere and I can't help but be unimpressed.
peterwwillis 12y ago
First OP says they want to find the likelihood, then they try to find the probability? Already I am skeptical of the methodology. "While it can be difficult to determine guilt in a single case, my intuition is that a person independently accused of assault by multiple people is quite unlikely to be innocent." Just so we're clear here: intuition is a heuristic, which is incredibly flawed and only intended to be used as a potential risk indicator for split-second decisions. Any time you hear of something risky you are more inclined to believe it because to not believe it would potentially open yourself up to risk. The only way to mitigate it is to have additional information or motive that overrides the unknown risk. Back to the model: they cite one study on sexual assault. Do you know how many actual studies there have been on sexual assault? Not many. Do you know how many of them had widely varying results? Most of them. Do you know how many had different methodologies which changed the nature of the model? All of them. So I guess let's ignore that someone could probably pick a different study that would change the results. So what does this particular study say? The study involved asking 2,000 men at one college in one state about their sex lives. (Random sampling? Who needs that?) Of those men, about six percent admitted to sex that fell under the legal definition of rape without consent of the woman, which includes force or alcohol. Consider for a moment that the legal guidelines basically say that if you have a bottle of wine with your girlfriend and you end up in bed together, it's rape if there wasn't a consent agreement. In this case they're only asking the men and making a judgement based on the legal framework, and not asking the women about their relationship or if there was consent, which could possibly change the results. But anyway, "I think the UVA episode illustrates precisely why statistics are so important -- because anything can happen in a single story, making it a risky thing to hang a cause on." So why would you create a model based on a single limited study, and not at the very least recreate your model based on the data from other studies? "Regardless of what really happened at UVA, the broader trend is clear: the rate of campus sexual assaults is high (20%, says CDC, although better data should be collected); the rate of false accusations is low (this review cites 6 studies which all yield estimates between 2% and 8%, lower than the rate of false reports for car theft)." Another study said the campus assaults were 90%. The CSA final report put it at 13.7%. And (all) the false accusation studies were collected and analyzed by Philip N.S. Rumney and determined that due to the unreliable research methodologies used, along with unreliable judgements by law enforcement, it was impossible to give a plausible statistic. I've always found that people rely on statistics when they want a nice simple number to sum up their opinions, and don't want to deal with the fact that there is no simple, clean way to summarize complicated, wide-ranging circumstances, events and behaviors.
nosespray 12y ago
Until the effect of media bombardment and other 'incidentals' can be given a weight, the whole thing is an exercise in futility.
pcthrowaway 12y ago
While interesting, this also completely fails to take into account motivations for targeting people with false accusations. For example, while Michael Jackson was accused of assault on two occasions, I think it's fair to also consider that the prospect of a financial payoff could be a motivation to press charges against him. In the first such case, he eventually settled for $15 million towards a trust fund for the accuser, despite no evidence and a strong case that the accusations were only levied as a money grab (the accuser was seeking a monetary settlement instead of criminal charges from the very beginning) In the second public accusation (years later), Michael was found innocent. Additionally, given the way things went in the first case, it is entirely believable that someone could see accusing Jackson of child molestation as a means to an easy payoff. I'm not saying Michael Jackson is innocent beyond all doubt, but the court clearly determined it was impossible to make a case that he was guilty beyond all doubt. I do think it's important to consider other factors in situations where assault (sexual or otherwise) is accused though. For what it's worth, I think it's very likely Bill Cosby is guilty of most of the allegations he is currently party to.
casebash 12y ago
"probability a non-DA will assault someone in a given encounter" - so according to this model, if someone has enough sexual encounters there is a near 100% chance that they will assault someone. That's kind of dodgy.
casebash 12y ago
"probability a non-DA will assault someone in a given encounter" - So this assumes that if someone has enough encounters that they will eventually have near 100% chance of committing assault.
mpweiher 12y ago
This is horribly wrong on so many levels. False reports/accusations of crime in general tend to be low, in the 2-8% range reported here. By this logic, we can dispense with this whole silly and expensive criminal justice system and just convict everyone based on simple accusation. We used to call this sort of thing "lynching", and it is generally considered a good thing that it's become rare. "It is better that ten guilty persons escape than that one innocent suffer"[1] Also note that the "low rate" for false accusations is for cases were the false accusation is proven: "The determination that a report of sexual assault is false can be made only if the evidence establishes that no crime was committed or attempted. This determination can be made only after a thorough investigation. This should not be confused with an investigation that fails to prove a sexual assault occurred. In that case the investigation would be labeled unsubstantiated. The determination that a report is false must be supported by evidence that the assault did not happen."[2][3] By this standard, cases of rape that are actually proven are also low, depending on where you look in the 7% range of reported[3]. So the "we just don't know" figure is very, very high, we simply do not have strong evidence either way[4]. Other studies have found false report rates much higher [5][6]. The Air Force study[6] is interesting in that admissions of false accusations increased dramatically when it became known that a Polygraph would be administered (though AFAIK, the Polygraph information itself was not used as indication of a false report, only an actual admission). The raw data of admitted false cases was then combined with other characteristics of those cases to develop a model for "likely" false accusations (things like "does the rape cause problems or solve problems for the accuser", "does the report follow widely assumed patterns of rape vs. real patterns", "do the injuries show patterns that are typical of self-infliction" etc.) With that model, applied conservatively, the false report rate was above 50%. There is also an interesting investigation showing that the 2% figure that pops up in many "studies" books and papers on the subject can all be traced to a single off-the-cuff, non-researched remark.[7] So the reference figures are at best flawed and way too uncertain to base a model on. Additionally, the statistics are incorrectly applied to a single event ("How likely is someone ..."). The statistics only work for a sufficiently large population. Finally, as many others have pointed out, the events are not uncorrelated, and the assumption that they are and that "lots of reports must mean there is something there" is a well-documented fallacy of human cognition. The McMartin case is an obvious one, but there is also the famous case of the French city of Orleans, where an entire city was convinced that girls were being drugged and abducted in fashion stores, which turned out to be completely unfounded.[8][9][10] So please pack up this model, or let's all just abandon our legal system, due process and meet for a happy lynching. [1] http://en.wikipedia.org/wiki/Blackstone's_formulation http://en.wikipedia.org/wiki/Blackstone's_formulation [2] http://yesmeansyesblog.wordpress.com/2010/09/09/false-rape-allegations-are-rare/ http://yesmeansyesblog.wordpress.com/2010/09/09/false-rape-a... [3] https://rainn.org/get-information/statistics/reporting-rates https://rainn.org/get-information/statistics/reporting-rates [4] http://lawprofessors.typepad.com/crimprof_blog/2004/12/2_false_rape_st.html http://lawprofessors.typepad.com/crimprof_blog/2004/12/2_fal... [5] http://www.informationisbeautiful.net/visualizations/rape-a-lack-of-conviction/ http://www.informationisbeautiful.net/visualizations/rape-a-... [6] http://www.fathersmanifesto.net/mcdowell.htm http://www.fathersmanifesto.net/mcdowell.htm [7] http://digitalcommons.lmu.edu/cgi/viewcontent.cgi?article=2216&context=llr http://digitalcommons.lmu.edu/cgi/viewcontent.cgi?article=22... [8] https://www.kirkusreviews.com/book-reviews/edgar-morin/the-rumor-in-orleans/ https://www.kirkusreviews.com/book-reviews/edgar-morin/the-r... [9] http://de.wikipedia.org/wiki/Gerücht_von_Orléans http://de.wikipedia.org/wiki/Gerücht_von_Orléans [10] http://fr.wikipedia.org/wiki/Rumeur_d'Orléans http://fr.wikipedia.org/wiki/Rumeur_d'Orléans
aratinga 12y ago
Why do I get the strange feeling that most of these comments were posted by males, I wonder? Leaving college aside, there has been a lot of discussion of rape in the military. Apparently there are a number of repeat predators, in an environment where bringing an accusation can result in the accuser's being thrown out of the military, shunned, or assaulted. (Male victims abound, by the way.) I would love to see this simulation with numbers based on the military experience. Meanwhile the military are reluctant to allow outside interference in their complicity with rape. The missing item in the reporting is how many of those accused were accused more than once. http://www.militarytimes.com/story/military/pentagon/2014/12/04/pentagon-rand-sexual-assault-reports/19883155/ http://www.militarytimes.com/story/military/pentagon/2014/12...

43 points by svtrent 12y ago

> The intuition that, “if you are accused of assault by multiple people, you’re probably guilty” is often accurate. Importantly, even if you were to choose settings where someone who has been accused once is more likely than not to be innocent, the probability of innocence often drops dramatically if they have been accused twice. This doesn't account for whether or not the accusations are independent of one another, which in this case most were not.

statistician409 12y ago
(I'm the author of the post) the fact that accusations may not be independent is of course important (although I'd question the aptness of the above commenter's comparison to witch trials); I'd welcome your suggestions for incorporating correlations into the model. This is one of the reasons the tool discussed in the NYT's article could be powerful -- because it allows us to be more confident that accusations were levied independently, since people submit to the tool without knowing about other accusers.
- logicallee 12y ago
  The comparison with witch trials is simple. People can be totally independent, and not know each other, and independently conclude that you're a witch. Why would they do this? Obviously due to some factor about you. The mistake you make is using Occam's razor to conclude that that factor is "being a witch". The other poster used the example of witches because we all know there is no such thing. There is 0% chance of someone being a witch, whom nobody has ever so much as suspected of being a witch. But there is also 0% of someone being a witch, about whom dozens of totally independent people, in different locations, throughout the person's life and career, have independently come to the firm and undeniable conclusion that they are a witch. This is why this was the example that was used.
  - darkhorn 12y ago
    Everyone says that [put some religion here] is true. All these people can't be wrong, can they be? Therefore this religion is true. Applies not only to religion but also to heating home, sickness, astrology, cutting penices of children etc.
    - logicallee 12y ago
      Not bad :) Author should post "How likely is someone to be the son of God based on number of disciples?" and we can see where 12 fits in.
- lectrick 12y ago
  You are not accounting for a few typical problems with these cases. 1) Eyewitness testimony ("personal accounts done a certain time after the event in question") is disappointingly terrible. http://www.scientificamerican.com/article/do-the-eyes-have-it/ http://www.scientificamerican.com/article/do-the-eyes-have-i... 2) The accuracy of human memory is disappointingly terrible. http://www.theatlantic.com/health/archive/2013/11/how-many-of-your-memories-are-fake/281558/ http://www.theatlantic.com/health/archive/2013/11/how-many-o... ... Especially under stress/duress/emotionally-charged events. https://en.wikipedia.org/wiki/Effects_of_stress_on_memory https://en.wikipedia.org/wiki/Effects_of_stress_on_memory Lastly, regarding the anonymous reporting tool cited in the NYTimes article- that is no different from an anonymous witchcraft reporting tool. Any single individual who accrues too much community ire (whether deserved or not) can get anonymously accused of something (and at minimum, publicly humiliated or reputation-damaged) by a collusive group of individuals (who can act with complete impunity due to anonymity). It is for this reason that I believe, difficult as it is to do, that all accusers should be known... unless we also allow anonymity to the accused while they fight off the accusations! A little bit more controversially (and I freely admit this may be ENTIRELY up for debate, YMMV), there may exist a false-accusation bandwagon effect due to the economic forces at play https://omegavirginrevolt.wordpress.com/2014/11/23/the-false-accusation-bandwagon-effect/ https://omegavirginrevolt.wordpress.com/2014/11/23/the-false... Essentially, each new woman who steps forward and does not file a criminal suit but a civil one makes it more likely that (for example) Cosby's liability insurer will force him to pay out to alleged victims regardless of actual guilt. In addition, the accuser, who is likely someone that the "fame" spotlight has left in the past, can enjoy some more time under it. You fail to account for the additional financial/fame ("perverse") incentive of joining a bandwagon in this regard, especially when the accused is a wealthy individual. I sincerely hope that the above does not come off as anti-victim, misogynist, or otherwise. I just think we need to remember the lessons from the Witchcraft Era as well as from psychology research of the past few years.
- lotharbot 12y ago
  > "people submit to the tool without knowing about other accusers" Not necessarily. People can conspire to submit multiple accusations to the tool against the same person. Even without actual conspiracy, someone who is a target for other reasons could have multiple false accusations independently levied against them. Example: I have a friend who runs a religious ministry for ex-members-of-another-religion. This draws the ire of current-members-of-the-other-religion, and leads to a lot of things they post being flagged as abusive (even things like photographs of themselves.) In some cases, it's clear that there's a group conspiring -- something posted years ago will get flagged multiple times over the course of a day (FB once investigated and located a private group that was being used to coordinate mass-flagging efforts.) In other cases, it's just the most recent thing they posted, likely being independently flagged.
- jamessb 12y ago
  Perhaps a better example of how a naive assumption of statistical independence has led to a severe miscarriage of justice is provided by the case of Sally Clark: https://en.wikipedia.org/wiki/Sally_Clark https://en.wikipedia.org/wiki/Sally_Clark I would be extremely wary of your claim that "multiple accusations enable us to get enough evidence to convict even in parameter regimes where a single accusation is never enough" (https://www.dropbox.com/sh/drrvcd5zzqclhbt/AACdWnx_wlfwnUoYFme9UgX9a/exercises_with_binomial_posterior_probabilities.pdf?dl=0 https://www.dropbox.com/sh/drrvcd5zzqclhbt/AACdWnx_wlfwnUoYF...).

darkhorn 12y ago

http://m.liveleak.com/view?i=db6_1370665965&comments=1 http://m.liveleak.com/view?i=db6_1370665965&comments=1

pekk 12y ago

Some centuries ago, there were periods when many people would get accused of consorting with the devil, and multiple witnesses would be brought forward to substantiate this, and many people were burned as a result. That's not just a problem of ancient superstition; as recently as the 90s, a number of people were convicted of Satanic Ritual Abuse, with multiple witnesses, and some of the real victims (often women working in places like daycare centers) have been in jail for decades on the basis of clearly unbelievable and coached testimony. Whenever one of these periods occurs, it's not a one-off act by some individual, nor even a matter of any specific religion. It's a clear indication that the justice system has been fundamentally compromised in the way it treats evidence and renders a final judgement. This article might have good intentions, but its method could be applied to witchcraft or Satanic Ritual Abuse, and obtain the same kinds of conclusions: If you're accused of witchcraft by multiple people, you're probably guilty. This is still mostly true if we don't believe that witches are a separate kind of people. Increasing our certainty that witches are witches is even good for the people who are accused of being witches. Counting up the number of accusations is clearly a wrong standard for determining that someone is guilty. The available evidence in each case matters, and accusations are not necessarily independent. The general presumption of innocence until proven guilty is still necessary and still applies to rape as to other crimes.

jmount 12y ago
I agree. A large count at best proves non-independence (or contamination). It really doesn't address if the contamination is a guilty party, a smear campaign or self-correlating accusations. The original article gave too much credence to the possibility of calculation solving this by even trying to work things as far as it did.
- Retra 12y ago
  That was my first thought on reading the title: a million accusations is no better than one unless you can prove they are independent.
philwelch 12y ago
The difference being that witchcraft and satanism were moral panics that never actually happened to anyone, and rape is something that actually happens to real people fairly often.

dahart 12y ago

> But how can we combine multiple accusations of assault, given that survivors are usually unaware of each other and often reluctant to come forward? I see the other comments pointing at this potential problem as well, but I'll phrase it as a question - since the article opens with a reference to Bill Cosby, is it even valid to combine multiple accusations of assault when the accusers are aware of each other, possibly through media exposure, and may have come forward as a result? And while there is a (perhaps unsurprising?) correlation between independent accusations and probability of guilt, how can this statistical approach be responsibly used, and should it, and what for? Assault is awful and I'm sure the majority of assaults with even one accuser is (or should be) straightforward), but it seems like there are other uncontrolled possibilities here besides the independence of accusations, like whether the accuser and accused know each other.

kaitai 12y ago
One way to deal with this is discussed in the article -- if details of reports are not widely publicized (often the case), then details of reports/allegations can be compared. In many cases, as noted in the post, methods are consistent. You could use some Bayesian analysis to figure out the probability that independent reports would come up with the same details.

jeffdavis 12y ago

This article is reckless. The author throws out a mathematical model regarding a very sensitive subject with no evidence that the model reflects reality. In effect, it just gives a mathematical veneer to the author's guesses. Similar to how wearing a lab coat while stating your opinion makes it seem scientific. (The most obvious issue is non-independence, but there are plenty of other problems.)

skj 12y ago
Exactly correct. It was more or less, "Given this model, my assumptions are correct!", completely missing the point that the model was the assumption itself.

crazypyro 12y ago

Is there any consideration taken for the fact that public figures, like celebrities, present a larger target, based on their wealth and fame? I'd imagine that would make a difference when compared with a regular person who is not in the public spotlight or doesn't have a large estate. Does this "intuitive thought" actually represent real world events?

kaitai 12y ago
Take a look at actual accusations of celebrities. Because of their wealth and fame, they are really good at sweeping these accusations under the rug. The first really public allegation against Cosby, for instance, was made public in 2002. Since it took until 2014 for anyone to care, it seems doubtful that the wealth and fame of celebs makes them "better" targets. It would be really interesting for someone to actually pull lists of famous celebrities from the last few decades (from mentions in media, for instance), look at rape accusations, and classify results. I don't know how you could compare to "regular" guys as most non-famous people don't make the news even if accused of rape, but a comparison of conviction rates could be illuminating.

Xcelerate 12y ago

My issue is more with smear campaigns. Leave the concern of guilt or innocence to the justice system. For every 100 people that are "probably" guilty on the basis of hearsay, how many innocent ones have had their reputation irreversibly ruined by widespread internet witch-hunts? If these people would focus their time and energy on actually coming up with solutions to the problems they're complaining about in their generality rather than targeting specific individuals (for instance, solving the problem of performance enhancing drugs in cycling vs creating a media sensation about Lance Armstrong), I think society would be much better off.

jeffdavis 12y ago

"the rate of false accusations is low" I didn't read the study, but how could anyone know this? I suppose you could assume that a conviction means that the accusation is true, and that exoneration means that accusation is false, but there are a lot of cases where it's not known one way or another. I would be surprised if 90%+ of accusations result in a conviction, so the study must be assuming that any accusation is true if the accused is not exonerated. There are also other, like if one party believes an assault took place and the other does not, or if the accusation is true but the perpetrator is misidentified. Please correct me if I'm wrong, but my guess is that the statement above (alone, out of context) is not well supported by evidence.

glenra 12y ago
You're correct, the rate of false accusations might be quite high. The "2-8%" stat given in OP really should be "2-10%" - advocates somehow tend to lose track of a couple studies that came out on the high end - but even that number range is only the percentage of rape accusations that were brought to the police which were deemed demonstrably false. For instance: the alleged victim reported it to the cops but later recanted or changed their story so much that it couldn't be trusted, or the facts on the ground made the story as stated impossible. Advocates are correct to note that this "2-10%" includes some mistakes - true rape victims might be very confused in their testimony or might recant because they get frustrated with the justice system - but it still should probably be regarded as a lower bound on the actual number of false accusations, as it's a subset of the full total. False accusations that wouldn't show up in this measurable "2-10%" include (a) those in which the accusation is plausible, consistent and the accuser does not recant, (b) false accusations that aren't ever brought to the police.
- rayiner 12y ago
  If we're not going to count false accusations that don't carry the threat of jail time, we should also look at cases where there was a rape but nothing was taken to the police.
- clay_to_n 12y ago
  Are you sure this can be considered a "lower bound"? The amount of people who were raped and never went to the police could be much higher than the amount of people who lied to the police about being raped.

deleted 12y ago

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darkhorn 12y ago

Not realated with statistics but this is how females think. This is a few years old real story I've heard, from Austria. There is some kind of part like graduation or something. A guy with his new girlfriend starts to make out. Before they start to make sex the guy asks to the girl her age. She replies that she is 16 or something like that. Then the fuys says that it is not approppriate and leaves her. Then the girl says to her friends that she was sexually abused... That he leaved her etc... Hello....????!!!

ceejayoz 12y ago
I'm glad we can determine "how females think" from a hearsay-based anecdote for which significant details are noted as "or something".
- darkhorn 12y ago
  Similar one http://www.gazetesok.com/yazi/alkol-varsa-tecavuz-sayilmaz_219814 http://www.gazetesok.com/yazi/alkol-varsa-tecavuz-sayilmaz_2...

grandalf 12y ago

What about the probability of someone who has been accused multiple times to also draw false accusations? True ones? What about the substantially different personal cost of making an immediate accusation vs a delayed one? The same applies to someone like Snowden who could have waited until he was in his 70s before blowing the whistle.

upside 12y ago

The author starts off with a Bill Cosby example, front and center, then continues to develop a stat model while acknowledging an inability to account for incidentals, while never mentioning that Bill Cosby is more than likely to have a significant number of incidentals.... Like, tonnes of money and hangin' out at playboy mansions where shady-ness pervades. Back in the day, pre-blogging, when journalism was actually a profession, journalists were taught to avoid this kind of set up. Now it's everywhere and I can't help but be unimpressed.

peterwwillis 12y ago

First OP says they want to find the likelihood, then they try to find the probability? Already I am skeptical of the methodology. "While it can be difficult to determine guilt in a single case, my intuition is that a person independently accused of assault by multiple people is quite unlikely to be innocent." Just so we're clear here: intuition is a heuristic, which is incredibly flawed and only intended to be used as a potential risk indicator for split-second decisions. Any time you hear of something risky you are more inclined to believe it because to not believe it would potentially open yourself up to risk. The only way to mitigate it is to have additional information or motive that overrides the unknown risk. Back to the model: they cite one study on sexual assault. Do you know how many actual studies there have been on sexual assault? Not many. Do you know how many of them had widely varying results? Most of them. Do you know how many had different methodologies which changed the nature of the model? All of them. So I guess let's ignore that someone could probably pick a different study that would change the results. So what does this particular study say? The study involved asking 2,000 men at one college in one state about their sex lives. (Random sampling? Who needs that?) Of those men, about six percent admitted to sex that fell under the legal definition of rape without consent of the woman, which includes force or alcohol. Consider for a moment that the legal guidelines basically say that if you have a bottle of wine with your girlfriend and you end up in bed together, it's rape if there wasn't a consent agreement. In this case they're only asking the men and making a judgement based on the legal framework, and not asking the women about their relationship or if there was consent, which could possibly change the results. But anyway, "I think the UVA episode illustrates precisely why statistics are so important -- because anything can happen in a single story, making it a risky thing to hang a cause on." So why would you create a model based on a single limited study, and not at the very least recreate your model based on the data from other studies? "Regardless of what really happened at UVA, the broader trend is clear: the rate of campus sexual assaults is high (20%, says CDC, although better data should be collected); the rate of false accusations is low (this review cites 6 studies which all yield estimates between 2% and 8%, lower than the rate of false reports for car theft)." Another study said the campus assaults were 90%. The CSA final report put it at 13.7%. And (all) the false accusation studies were collected and analyzed by Philip N.S. Rumney and determined that due to the unreliable research methodologies used, along with unreliable judgements by law enforcement, it was impossible to give a plausible statistic. I've always found that people rely on statistics when they want a nice simple number to sum up their opinions, and don't want to deal with the fact that there is no simple, clean way to summarize complicated, wide-ranging circumstances, events and behaviors.

nosespray 12y ago

Until the effect of media bombardment and other 'incidentals' can be given a weight, the whole thing is an exercise in futility.

pcthrowaway 12y ago

While interesting, this also completely fails to take into account motivations for targeting people with false accusations. For example, while Michael Jackson was accused of assault on two occasions, I think it's fair to also consider that the prospect of a financial payoff could be a motivation to press charges against him. In the first such case, he eventually settled for $15 million towards a trust fund for the accuser, despite no evidence and a strong case that the accusations were only levied as a money grab (the accuser was seeking a monetary settlement instead of criminal charges from the very beginning) In the second public accusation (years later), Michael was found innocent. Additionally, given the way things went in the first case, it is entirely believable that someone could see accusing Jackson of child molestation as a means to an easy payoff. I'm not saying Michael Jackson is innocent beyond all doubt, but the court clearly determined it was impossible to make a case that he was guilty beyond all doubt. I do think it's important to consider other factors in situations where assault (sexual or otherwise) is accused though. For what it's worth, I think it's very likely Bill Cosby is guilty of most of the allegations he is currently party to.

casebash 12y ago

"probability a non-DA will assault someone in a given encounter" - so according to this model, if someone has enough sexual encounters there is a near 100% chance that they will assault someone. That's kind of dodgy.

casebash 12y ago

"probability a non-DA will assault someone in a given encounter" - So this assumes that if someone has enough encounters that they will eventually have near 100% chance of committing assault.

mpweiher 12y ago

This is horribly wrong on so many levels. False reports/accusations of crime in general tend to be low, in the 2-8% range reported here. By this logic, we can dispense with this whole silly and expensive criminal justice system and just convict everyone based on simple accusation. We used to call this sort of thing "lynching", and it is generally considered a good thing that it's become rare. "It is better that ten guilty persons escape than that one innocent suffer"[1] Also note that the "low rate" for false accusations is for cases were the false accusation is proven: "The determination that a report of sexual assault is false can be made only if the evidence establishes that no crime was committed or attempted. This determination can be made only after a thorough investigation. This should not be confused with an investigation that fails to prove a sexual assault occurred. In that case the investigation would be labeled unsubstantiated. The determination that a report is false must be supported by evidence that the assault did not happen."[2][3] By this standard, cases of rape that are actually proven are also low, depending on where you look in the 7% range of reported[3]. So the "we just don't know" figure is very, very high, we simply do not have strong evidence either way[4]. Other studies have found false report rates much higher [5][6]. The Air Force study[6] is interesting in that admissions of false accusations increased dramatically when it became known that a Polygraph would be administered (though AFAIK, the Polygraph information itself was not used as indication of a false report, only an actual admission). The raw data of admitted false cases was then combined with other characteristics of those cases to develop a model for "likely" false accusations (things like "does the rape cause problems or solve problems for the accuser", "does the report follow widely assumed patterns of rape vs. real patterns", "do the injuries show patterns that are typical of self-infliction" etc.) With that model, applied conservatively, the false report rate was above 50%. There is also an interesting investigation showing that the 2% figure that pops up in many "studies" books and papers on the subject can all be traced to a single off-the-cuff, non-researched remark.[7] So the reference figures are at best flawed and way too uncertain to base a model on. Additionally, the statistics are incorrectly applied to a single event ("How likely is someone ..."). The statistics only work for a sufficiently large population. Finally, as many others have pointed out, the events are not uncorrelated, and the assumption that they are and that "lots of reports must mean there is something there" is a well-documented fallacy of human cognition. The McMartin case is an obvious one, but there is also the famous case of the French city of Orleans, where an entire city was convinced that girls were being drugged and abducted in fashion stores, which turned out to be completely unfounded.[8][9][10] So please pack up this model, or let's all just abandon our legal system, due process and meet for a happy lynching. [1] http://en.wikipedia.org/wiki/Blackstone's_formulation http://en.wikipedia.org/wiki/Blackstone's_formulation [2] http://yesmeansyesblog.wordpress.com/2010/09/09/false-rape-allegations-are-rare/ http://yesmeansyesblog.wordpress.com/2010/09/09/false-rape-a... [3] https://rainn.org/get-information/statistics/reporting-rates https://rainn.org/get-information/statistics/reporting-rates [4] http://lawprofessors.typepad.com/crimprof_blog/2004/12/2_false_rape_st.html http://lawprofessors.typepad.com/crimprof_blog/2004/12/2_fal... [5] http://www.informationisbeautiful.net/visualizations/rape-a-lack-of-conviction/ http://www.informationisbeautiful.net/visualizations/rape-a-... [6] http://www.fathersmanifesto.net/mcdowell.htm http://www.fathersmanifesto.net/mcdowell.htm [7] http://digitalcommons.lmu.edu/cgi/viewcontent.cgi?article=2216&context=llr http://digitalcommons.lmu.edu/cgi/viewcontent.cgi?article=22... [8] https://www.kirkusreviews.com/book-reviews/edgar-morin/the-rumor-in-orleans/ https://www.kirkusreviews.com/book-reviews/edgar-morin/the-r... [9] http://de.wikipedia.org/wiki/Gerücht_von_Orléans http://de.wikipedia.org/wiki/Gerücht_von_Orléans [10] http://fr.wikipedia.org/wiki/Rumeur_d'Orléans http://fr.wikipedia.org/wiki/Rumeur_d'Orléans

aratinga 12y ago

Why do I get the strange feeling that most of these comments were posted by males, I wonder? Leaving college aside, there has been a lot of discussion of rape in the military. Apparently there are a number of repeat predators, in an environment where bringing an accusation can result in the accuser's being thrown out of the military, shunned, or assaulted. (Male victims abound, by the way.) I would love to see this simulation with numbers based on the military experience. Meanwhile the military are reluctant to allow outside interference in their complicity with rape. The missing item in the reporting is how many of those accused were accused more than once. http://www.militarytimes.com/story/military/pentagon/2014/12/04/pentagon-rand-sexual-assault-reports/19883155/ http://www.militarytimes.com/story/military/pentagon/2014/12...