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All of rolf_nelson's Comments + Replies

Experiment: Knox case debate with Rolf Nelson

I finally got around to reading through the appeal motivation and the relevant parts of the Conti-Vecchiotti report, and I find nothing to lend credence to the innocence hypothesis. If anything, I would judge the timing of the double-DNA knife testing seems to move the 'laboratory contamination' hypothesis from very very very unlikely to very very very very unlikely.

So in the end, I have to apologize to kompinisto as I have inadvertently wasted both of our time in suggesting this debate; our failure to reach a consensus on an accurate truth in this issue is a mild lose-lose.

Experiment: Knox case debate with Rolf Nelson

rolf_nelson12y1

As it happens, in the present case, the only material found in the small intestine was at the very end, near the ileocecal valve.

I agree, but I don't know whether other material would have been found if present. Is searching the entire small intestine feasible, and if so was such a search performed? Would food in the middle of the small intenstine after death have continued to digest?

Prof. Umani Ronchi, at the hearings of 04-19-2008 and 9-19-2009, never discussed "an imperfect application of the ligatures" at the duodenal level, but rather t

rolf_nelson12y0

So to be absolutely clear, then: taking into account all the information you are aware of, and adjusting for systematic uncertainty, what are your current probabilities of guilt conditioned on death having occurred during the following intervals?:

.95 for all the scenarios mentioned, maybe a little less for the 21:00-21:30.

On the contrary, see here for example.

Good find, and it slightly bolsters the case against Knox: contents don't pass into the duodenum after death (which I expected), and other unspecified parts of digestion continue after death (w... (read more)

Experiment: Knox case debate with Rolf Nelson

rolf_nelson12y4

Thanks for another well-researched reply, let's have a couple more posts on this, and then turn to the DNA for a bit.

On the other hand, if we do take systemic uncertainty into account (as we ultimately must), a shift of 15:1 or even 5:1 would be significant, given your estimate of .95 probability of guilt, or 19:1 odds.

The problem is that systemic uncertainty works both ways. If I see there being, say, 10 times as much evidence for guilt then there is for innocence, I'll still cap the probability of guilt at .95 anyway, due to systemic uncertainty. If ... (read more)

0komponisto12y

So to be absolutely clear, then: taking into account all the information you are aware of, and adjusting for systematic uncertainty, what are your current probabilities of guilt conditioned on death having occurred during the following intervals?: (1) 21:00 - 21:30 (2) 21:30 - 22:00 (3) 22:00 - 23:00 (4) 23:00 - 23:30 (5) after 23:30 (Be sure to check for consistency with your probability distribution for time-of-death and your overall probability of guilt.) That sounds like a point about priors, rather than systemic uncertainty. What I want to know is the following: if I could show that the time of death was before 21:30, or before 22:00 (etc.), how far would that reduce your current guilt-probability of 95%? (Obviously, if the answer is "negligibly", then there isn't any point in discussing gastric lag time.) On the contrary, see here [http://books.google.com/books?id=6bW4WSRgfKoC&pg=PA109&lpg=PA109&dq=%22duodenum%22+empty++%22time+of+death%22&source=bl&ots=CeyfGy0xjw&sig=K6mxyFIjgsGtluc0WEZfAPay4Vs&hl=en&ei=ScBETvSVE5TPgAed4724Bg&sa=X&oi=book_result&ct=result&resnum=3&ved=0CCUQ6AEwAg#v=onepage&q=%22duodenum%22%20empty%20%20%22time%20of%20death%22&f=false] for example. (By the way, it's actually Sollecito's defense; the matter is not discussed in Knox's appeal document.) The literature often emphasizes that gastric contents are of limited reliability in determining time of death. However, there is a specific circumstance in this case that make it atypically informative: the fact that the duodenum was completely empty, which by default implies that the entire meal was still in the stomach (modulo slippage issue discussed below). This puts a tighter bound on the time of death than in a more typical situation with some smaller fraction of the meal in the stomach. I'm not sure how to make sense of this. What matters here is not the emptiness of the duodenum by itself, but rather the conjunction of the empty duodenum with the non-empty stomach. In other words, th

Experiment: Knox case debate with Rolf Nelson

rolf_nelson12y3

I would sooner hypothesize that Meredith's last meal actually took place closer to 19:00 than 18:00, given the vagueness of the testimony on the matter. This puts her within 2 standard deviations, perhaps even 1.5.

If we model the meal start-time as a normal distribution, then it'll be simple to add it to the model and combine it with the other sources of uncertainty, since two normal distributions sum to a new normal distribution with a variance equal to the sum of the variances. Though now that I mention it, a lot of the other bits of uncertainty might... (read more)

1komponisto12y

If we don't take systemic uncertainty into account, then 15:1 isn't much of a shift in the face of numbers like 2500:1 or 200000:1 that you were giving for the knife. On the other hand, if we do take systemic uncertainty into account (as we ultimately must), a shift of 15:1 or even 5:1 would be significant, given your estimate of .95 probability of guilt, or 19:1 odds. Crudely approximating this as 20:1, it would take you down to 4:3 (p = 4/7 = 0.57) or 4:1 (p= 4/5 = 0.8) respectively. I imagine that if you were to believe the 21:26 computer interaction, the pre-22:00 odds could potentially go down to something like 4:3 as well. This indicates that it may be worthwhile to keep pursuing the time-of-death issue. Well, I was already assuming that you didn't believe Curatolo (for one thing, he gives Amanda and Raffaele an alibi for 21:30-23:00!). If you do, that will have to be dealt with separately. But in general, not only is eyewitness testimony among the weakest forms of evidence, but it cuts both ways in this case, as the broken-down car illustrates. Keep in mind, however, that Ronchi's speculation about slippage was based on the mistaken assumption that ligatures had not been applied. So there may not be as much contradiction here as it appears (especially since it isn't clear to me that the FRCPath's opinion necessarily pertained to the non-ligature case, depending on how standard ligatures are). How much slippage do you think may have occurred? If you can find a reference to support the idea that a lag time in excess of four or even three hours would not be highly unusual for a small-to-moderate pizza meal eaten by a healthy adult human, I will update appropriately. Conversely, if you can't (and I haven't been able to so far), I don't see how you can derive the level of uncertainty you need to make the Massei theory plausible in the face of all the other data. Even acknowledging the wide variation in lag times depending on the type of meal used in the studie

4Paul Crowley12y

I'm not following this discussion in detail, but I'm glad you guys are having it - I think it's a worthwhile case study, and the flavour of the way it's discussed is informative without getting into the detail of the subject matter.

Experiment: Knox case debate with Rolf Nelson

rolf_nelson12y-1

Surely you meant the defense appeal document here?

Yes, typo.

My interpretation of Ronchi doesn't depend on the defense appeal; it's simply the common-sense default meaning of what he said, as reported in Massei-Cristiani...

I don't agree with your common-sense default meaning in the English translation, then, although of course the original Italian may be more enlightening.

...and confirmed by general information about average gastric emptying times.

That reasoning seems circular to me: the question of what the times are in this case, is exactly wha... (read more)

1komponisto12y

The term used (in Massei-Cristiani) is svuotamento gastrico, which is a pretty literal counterpart of "gastric emptying". If someone says "X takes Y hours to empty", I view it as the default assumption that they are talking about the time it takes to empty completely (not to start emptying or empty halfway). Do you have a different view? Ronchi is reported by Massei and Cristiani as having said that "gastric emptying" can sometimes take 6-7 hours; we want to know whether he meant total emptying, or just half-emptying (or something else). So I searched and found a reference [http://www.vivo.colostate.edu/hbooks/pathphys/digestion/basics/transit.html] stating that total emptying (with the meaning unambiguous, explicitly contrasted to other parameters) typically takes 4-5 hours, in contrast to half-emptying, which typically takes 2.5-3 hours. For me this increases the (already high) probability that total emptying, and not half-emptying, was what was meant. Here are some factors that you may not be adequately considering: 1. Argument screens off authority [http://lesswrong.com/lw/lx/argument_screens_off_authority/]. Whatever the appropriate default assumptions about reliability may be, both the court and the defense have explained their arguments in detail (in lengthy documents that are publicly avaliable), while being in a position to know what each other's arguments are. There is unlikely to be much important information not contained in these documents. In particular, if the prosecution case is correct and the defense case isn't, we should expect to be able to determine this from the court's opinion and the appeal documents (without requiring further "rebuttal" from the court), since the court will have heard the defense case already, and should be anticipating the strongest possible defense reply; we should in other words expect to perceive the defense appeals as substantively weak, while perhaps demonstrating legal cleverness. If instead we perceive them as str

Experiment: Knox case debate with Rolf Nelson

rolf_nelson12y0

Just replied here: http://lesswrong.com/r/discussion/lw/6k7/experiment_knox_case_debate_with_rolf_nelson/4liq

Experiment: Knox case debate with Rolf Nelson

rolf_nelson12y0

Great, give me a top-level post when the knife translation is finished, or when you think it's in a good enough state to back up your claims in the dna discussion.

Experiment: Knox case debate with Rolf Nelson

rolf_nelson12y0

Reply to: http://lesswrong.com/r/discussion/lw/6k7/experiment_knox_case_debate_with_rolf_nelson/4jmb

Didn't realize you updated, looks like we can't go more than 8 or 9 deep before the RSS feed stops notifying about thread changes.

In terms of narrowing down what Umani Ronchi was actually saying, saying that the prosecution claims something in its appeals document isn't useful evidence. If there's a specific quote of Umani Ronchi that the prosecution makes, that might be useful, as long as the quote is clear enough that we can deduce it isn't being quoted ou... (read more)

0komponisto12y

Surely you meant the defense appeal document here? (I haven't referenced the prosecution appeal, and there wouldn't be much reason to, since it's just a 20-page rant arguing that Amanda and Raffaele are really nasty people and deserve a harsher sentence than the Massei court gave them.) My interpretation of Ronchi doesn't depend on the defense appeal; it's simply the common-sense default meaning of what he said, as reported in Massei-Cristiani, and confirmed by general information about average gastric emptying times. But even if it did, the appeal documents constitute the defense's reply to the Massei-Cristiani report, and so I don't see why they are any less useful than the latter. They rely on the same records that Massei and Cristiani do. Interestingly, p. 390 says the opposite: that Meredith had not consumed alcohol, according to Lalli. (And indeed it has been suggested by others elsewhere that the alleged small gastric alcohol level could have been due to a fermentation reaction). However, this is unlikely to be an important issue, as you point out. Of course, this is not the only internal contradiction in the document: Indeed, it seems the only way to know for sure which of these passages (if either) is accurate would be to have a transcript of Introna's testimony, which we unfortunately don't have. However, it's pretty clear in any case that Introna would exclude the Massei timeline of post-23:00. I would sooner hypothesize that Meredith's last meal actually took place closer to 19:00 than 18:00, given the vagueness of the testimony [http://masseireport.wordpress.com/contents/merediths-friends/] on the matter. This puts her within 2 standard deviations, perhaps even 1.5. But, granting a non-normal distribution, it's really difficult for me to see how it could significantly work against Raffaele, given where the 25th and 75th percentiles are. Probability mass would have to be transferred to the extreme right tail from somewhere else; how do you propose

Experiment: Knox case debate with Rolf Nelson

rolf_nelson12y0

Let's talk about the dna some more once you guys have finished translating the relevant parts of the independent report, then, if your argument hinges on details of the independent report rather than just the conclusions.

We're talking here not about the time it takes for the stomach to emtpy completely, but rather the time it takes for ingesta to begin passing into the duodenum ("T_lag").

Sounds good. In your case, for one particular meal where the subjects had probably fasted beforehand, the lag is just under 2/3 of the half-time. If you acce... (read more)

0komponisto12y

The translation [http://knoxdnareport.wordpress.com] is now nearing completion (the clasp section is finished, and the knife section will be soon). Here, furthermore, are some relevant links: * Expert commentary on C-V report: http://forensicdnaconsulting.wordpress.com/2011/07/30/understanding-the-independent-dna-experts%E2%80%99-report-in-the-amanda-knox-case-part-i/ [http://forensicdnaconsulting.wordpress.com/2011/07/30/understanding-the-independent-dna-experts%E2%80%99-report-in-the-amanda-knox-case-part-i/] * Article detailing contamination issues and other problems with DNA testing: http://www.nacdl.org/public.nsf/0/6285f6867724e1e685257124006f9177 [http://www.nacdl.org/public.nsf/0/6285f6867724e1e685257124006f9177] * Examples of laboratory fraud and how they were detected: http://www.bioforensics.com/conference05/FBS_Dayton_2005_Fraud.pdf [http://www.bioforensics.com/conference05/FBS_Dayton_2005_Fraud.pdf] * 9 DNA experts sign open letter [http://friendsofamanda.org/files/KnoxSollecitoDNAPetitionSubmitted11.19.09b.pdf] critiquing evidence near the end of the first trial: http://www.newscientist.com/article/dn18215-knox-murder-trial-evidence-flawed-say-dna-experts.html [http://www.newscientist.com/article/dn18215-knox-murder-trial-evidence-flawed-say-dna-experts.html] * Chris Halkides' blog: http://viewfromwilmington.blogspot.com [http://viewfromwilmington.blogspot.com]

0komponisto12y

As best I can determine, Ronchi was talking about total emptying time, not half-time (let alone lag time). This is unquestionably what would make the most sense, given not only the term used ("gastric emptying"), but also the averages presented, for example, here [http://www.vivo.colostate.edu/hbooks/pathphys/digestion/basics/transit.html]: * 50% of stomach contents emptied: 2.5 to 3 hours * Total emptying of the stomach: 4 to 5 hours Given this, a total emptying time of 6-7 hours under some cirumstances doesn't seem outside the bounds of possibility. Extrapolating in such a way as to preserve ratios, we could then imagine a half-time of up to 4.5 hours, say. But 2/3 of that would give us 3 hours, or 180 minutes -- not the 4-5 hours we need for the prosecution theory. Not according to p. 180 of Massei-Cristiani, where Introna is described as placing it between 21:00 and 21:30. Raffaele's appeal document argues for 21:30 - 22:00; this is apparently obtained by averaging the 2-3 hour (from last meal) figure of Lalli and Introna, and the 3-4 hour figure of Ronchi (whose testimony was incorrectly interpreted by Massei and Cristiani, according to the appeal: Raffaele's lawyers cite passages where he appeared to agree that 4 hours is the normal limit). My "disagreement" with Raffaele's lawyers in this context is of little import, for several reasons: (1) I am in perfect agreement with Introna, as reported by Massei; (2) We're talking about confidence intervals anyway; I think 21:00-21:30 is most likely, but 21:30-22:00 is not ruled out nearly as strongly in my model as anything after 22:00 is; (3) Ronchi, whose estimate figured into their calculation, was talking about total emptying time anyway, not lag time (or even half time). As for Vinci, he was looking at different criteria for the time of death (not specifically gastric contents), and simply gave a wider range, not an incompatible one. No disagreement here that I am aware of. Sure; just remember that the com

Experiment: Knox case debate with Rolf Nelson

rolf_nelson12y2

So making progress would probably require us to pick a small number of narrowly-defined issues to hash out, one at a time.

Sounds good, like you suggested let's cover the time of death, and also continue to go deep on the question of lab contamination.

Here's an important question to assess whether we've said anything important yet: has anything I've said surprised you?

It hasn't been predictable, but it hasn't caused me to shift significantly in favor of innocence or guilt so far. I did learn I was wrong about which knife Amanda reacted strongly to, b... (read more)

2komponisto12y

We're talking here not about the time it takes for the stomach to emtpy completely, but rather the time it takes for ingesta to begin passing into the duodenum ("T_lag"). (At death, there was 500mL of ingesta in the stomach -- consistent with the meal size -- and nothing in the duodenum.) According to this paper [http://onlinelibrary.wiley.com/doi/10.1111/j.1440-1746.2006.04449.x/abstract], the median value of T_lag is 81.5 minutes, and the 75th percentile is 102 minutes. (Furthermore, the median time for half the contents to empty ["T_1/2"] is 127 minutes, and the 75th percentile is 168.3 minutes.) The prosecution scenario of death during the 11:00 pm hour would require a T_lag of more than 240 minutes, possibly more than 300. My understanding is that this is basically unheard of, whatever the composition of the meal. Ronchi claimed that the coroner, Lalli, had failed to seal the duodenum via ligature, as is apparently the standard procedure; this was the basis for his claim that food could have slipped into the small intestine. However, video of the autopsy revealed that Ronchi was wrong, and that Lalli had indeed properly sealed the duodenum. (Sollecito appeal, p. 165) There were four samples on the blade, B,C,E, and G that were tested for blood; the results were all negative. These traces were all presumed to be blood by Stefanoni; it seems reasonable to suppose that if there had been blood on the knife, these would have been the most likely spots in which to have found it. A positive blood test result would require more than DNA from (white) blood cells -- it would require hemoglobin. So it seems to me that the only way to get a positive blood test result from contamination would be to spill a blood sample on the knife. I estimate the probability of this having happened as being in the range of 0.001. On the other hand, in the event that the knife had been used for stabbing, and that the victim's DNA remained on the knife, I would estimate a probability nor

Experiment: Knox case debate with Rolf Nelson

rolf_nelson12y0

While it remains interesting, we don't seem to be getting any traction toward significantly changing each other's mind through this one-on-one debate, should we just cut our losses and end it? I'm open to other suggestions on how to proceed. You haven't yet presented arguments toward innocence, but if we just follow the same pattern we have been so far we're probably not going to get anywhere with those either. Probably the only thing we can agree on is that at least one of us is biased on this case. ;-)

If you want to proceed, I'll ask you whether you agre... (read more)

2komponisto12y

I wouldn't have expected us to have made much progress on mind-changing by this point, since we've only had a couple of iterations of back-and-forth; and moreover we've been starting to succumb to the danger of going "shallow and wide" (i.e. listing disagreements on many different aspects of the case) rather than "narrow and deep" (i.e. trying to iron out a particular important point of disagreement). For instance, I think the contrasting opinions on the wounds, or inferences about how the knife was held, are areas of lesser importance, which we probably don't even need to get into at this point, since there are much more important issues to focus on (such as how likely contamination is, or the incompatibility of the stomach evidence with the prosecution's hypothesized time of death). So making progress would probably require us to pick a small number of narrowly-defined issues to hash out, one at a time. Here's an important question to assess whether we've said anything important yet: has anything I've said surprised you? That may be right, so if we do continue further it will be best to try to avoid that pattern. In any case, I think it's probably worthwhile for me to at least state for the record what I believe to be the most important arguments for innocence, so I'll go ahead and do that. Here are what I would consider to be the three strongest arguments for innocence, from a starting prior of "Knox and Sollecito have been convicted": (1) The hypothesized crime would be so singularly unusual as to make a miscarriage of justice a priori as likely as guilt, even without knowledge of defense arguments. In other words, the base rate of crimes in this reference class is less than or equal to the base rate of wrongful convictions. (2) Guede is unquestionably guilty. Hence, Meredith Kercher's death itself does not require explanation. (There is furthermore little connection between Guede and either Knox or Sollecito.) (3) The stomach evidence is incompatible with

Experiment: Knox case debate with Rolf Nelson

rolf_nelson12y0

I don't currently have a formal calculation. If you're curious, my current P(guilty) is .95; I'm reluctant to go higher due to the structural uncertainty inherent in any "trial by media". One way to summarize my current position is that I believe most of the court's findings (as in the Massei report) seem basically correct, and that correcting for demographics doesn't look to be nearly enough to swing the needle from guilt to innocence.

Experiment: Knox case debate with Rolf Nelson

rolf_nelson12y0

a smaller knife would have been compatible with all of the wounds as well as the imprint

(Massei, 170) seems to disagree (although I could be misreading it), but I welcome any counter-arguments. If you want to claim extreme coroner bias or extreme trial-court bias (or both), then eventually you'll want to separate out the hypothesis of bias and make your case for it.

The closest thing to evidence for (the knife being bleached) is that a police officer claimed to have smelled bleach upon opening the drawer that the knife was in. (That doesn't distinguish

... (read more)

2komponisto12y

The argument there is pretty weak: Massei and Cristiani simply find it hard to believe that a single knife could have caused such different-looking wounds. Not much more than an argument from personal incredulity; they don't support it with any detailed arguments or expert opinions indicating incompatibility of a smaller knife. In fact, they proceed to argue at length that Item 36 itself is compatible with all the wounds, by disputing the defense arguments that it is incompatible with some of them. (For counterarguments on this, see pp. 36-51 of Knox's appeal document [http://www.injusticeinperugia.org/Amanda_Knox_Appeal.pdf], and pp. 20-23 of Sollecito's [http://www.injusticeinperugia.org/Raffaele_Sollecito_Appeal.pdf]. Since you cited the original page number of Massei, I'm guessing you can read Italian. If not, I can provide translations. Briefly, the important things to note, besides the object-level defense arguments themselves, are that prosecution expert Bacci "disavowed" his earlier judgement of compatibility, and that civil-party expert Liviero wasn't even aware of the defense experts' counterarguments and hadn't considered them.) Such a statement strikes me as extremely weak evidence, likely tainted by hindsight among other things. Bleaching is the kind of thing you establish with chemical tests, not someone's judgement of "looking clean". Firstly, since we don't have the transcript of the interrogation, we don't know that it was a "lie". It could, for example, have been an exchange like this: But in any case my probability that he would make up some story similar to this (or otherwise say something that would likely be reported as him making up such a story), given (1) innocence, (2) that he had been told about the DNA result, and (3) had demonstrated confusion about his memories elsewhere (e.g. suggesting at one point that Knox had gone out on the evening of the crime), is in the region of 50%. People tend to trust authorities, and defying the data [h

Experiment: Knox case debate with Rolf Nelson

rolf_nelson12y0

So we're probably talking about an order of magnitude increase in the base rate: more like 1/5 instead of 1/50.

I'll posit a factor of three.

(Incidentally, there was never any "first independent report" prior to this one...)

My bad, that was quite confusing of me, I mean the Massei(+Cristiani) report, which is independent of the police lab. Will fix. Thanks!

The sample in question (Trace B) tested negative for blood, as did every other sample taken from the blade.

IMHO irrelevant, Meridith's DNA is incriminating whether it's from blood or... (read more)

2komponisto12y

Nonetheless, conditioned on Meredith's DNA being present, a negative blood test is surely significant evidence in favor of contamination over guilt, isn't it? If it was contamination, you would expect this with near certainty; whereas if the knife had been used to kill Meredith, what are the chances that any cleaning job was good enough to leave no trace of blood, yet bad enough to leave not only Meredith's DNA, but also granules of starch [http://knoxdnareport.wordpress.com/contents/conclusions-2/]? I'm not sure what you mean by "LCN aside"; LCN would seem integral to such a claim, since ordinary standards would already constitute sloppiness in the LCN context. But anyway I'm not sure I need to introduce such a hypothesis, since my beliefs about the unreliability of the knife result do not particularly depend on any beliefs I have about reliability of results in the average lab. It suffices for my purposes that the facts mentioned by Conti and Vecchiotti are Bayesian evidence of contamination given general scientific "common sense". While I currently think it unlikely that Stefanoni's level of sloppiness is typical, if it turned out that it was, that would sooner undermine my confidence in forensic lab results in general than my beliefs about this case. Formally, in other words, I view the base rate of contamination as being screened off [http://wiki.lesswrong.com/wiki/Screening_off] by the detailed information about lab procedures, rather than an independent piece of evidence to be weighed.

Experiment: Knox case debate with Rolf Nelson

rolf_nelson12y0

My guess is it's probably figured by assuming there are ~500 objects being examined by the lab.

Correct, I'm guessing a mean of roughly 500 examinations per homicide investigation.

...if there is a single contamination, there are likely to be others as well (reported or not).

Agree.

Experiment: Knox case debate with Rolf Nelson

rolf_nelson12y2

Thanks k, today I'll give my thoughts on the knife. I'm sure there are some mistakes in my analysis below, but let's see if we can start to pinpoint areas of disagreement. Let "ddk.lc" be the specific hypothesis that the double-dna knife was accidentally contaminated in the laboratory, and "a.g" be the hypothesis that Amanda is guilty.

I want to estimate the base rate of lab cross-contamination in the late 2000's. Two observations:

Looks like Washington State only admitted to one case of laboratory cross-contamination in homicide cases

... (read more)

0Wei_Dai12y

I'm having trouble understanding this. Can you explain a bit more? How did you get .002?

4komponisto12y

Okay, so, obviously a lot of disagreement here. Regarding the base rate of contamination, the first thing to remember is that in the case of the knife we're dealing with a Low Copy Number [http://en.wikipedia.org/wiki/Low_copy_number] (LCN) sample, for which the risk of contamination is greatly increased unless extremely stringent protocols are followed -- protocols which were not followed here. So we're probably talking about an order of magnitude increase in the base rate: more like 1/5 instead of 1/50. (Incidentally, there was never any "first independent report" prior to this one: the defense's request for an independent review during the first trial was rejected. What you are most likely referring to is the fact that Stefanoni's own bosses at the Polizia Scientifica signed off on her work, well before the trial. Based on what's in the Conti-Vecchiotti report I consider it likely that they didn't scrutinize it very carefully.) Secondly, thanks to Conti and Vecchiotti, we have considerable Inside View information about the reliability of this sample in particular. And there's every reason to believe this result is completely bogus. Indeed, Conti and Vecchiotti come pretty close to accusing Stefanoni of outright scientific fraud. Here are some of their observations: * The sample in question (Trace B) tested negative for blood, as did every other sample taken from the blade. (Samples from the handle were not tested for blood.) No attempt was made to scientifically determine the actual nature of the alleged biological material. * When "quantification" (test to determine whether there was enough DNA to be analyzed) was performed, Traces B and C both yielded a result of "too low". Stefanoni reported Trace B as a positive result, and Trace C as a negative result, without any justification. There is no documentation in the lab data to support her statement in court that the Trace B sample was in the range of several hundred picograms. Stef

Experiment: Knox case debate with Rolf Nelson

rolf_nelson12y1

I tentatively disagree on the interpretation of the experts' report, 'reliability' means a different thing for court DNA procedure vs. Bayesian analysis. I doubt they would say, "this kind of thing is 99% likely to point to the correct suspect, so it is mostly reliable by our standards".

2komponisto12y

If they didn't have the option of saying that, then it's hard for me to see what the point of the review was. Is it your position that Conti and Vecchiotti would have been likely to use the same strong language as they did, regardless of the position of this evidence along the continuum of reliability? Could they have said anything harsher if it were truly unreliable? Do you think a similar review of the DNA evidence against Guede would have produced a similar level of criticism?

Making an Amanda Knox prediction market

rolf_nelson12y2

That's a problem that would presumably exist to some extent on any public forum. I'm not too bothered by it myself; my feeling is that in such a situation one is not necessarily obliged to reply to all comments individually.

We could access-control the main section of a Google Group or a mini-blog, creating a separate area for comments if we like. That would also be convenient because I can easily notice if you've posted when I check Google Reader.

Here's my suggestion: why don't we try it here first, and see how it works? I'd be interested to see if th

... (read more)

0komponisto12y

New thread here [http://lesswrong.com/r/discussion/lw/6k7/experiment_knox_case_debate_with_rolf_nelson/]; reply to this comment here [http://lesswrong.com/r/discussion/lw/6k7/experiment_knox_case_debate_with_rolf_nelson/4hfu].

Making an Amanda Knox prediction market

rolf_nelson12y0

That'd be great! What forum should we use, should we start a Google Group? We can do it here if you like, but I'm concerned about getting distracted by other comments; the original threads got too bulky to hold a coherent conversation. It's up to you.

For my part, I'm happy to walk through the Micheli report or one of the many lists of evidence against Knox and Sollecito on the Internet, but I would pick as my top three pieces of evidence:

The double-DNA knife
Sollecito's DNA on Kercher's bra strap
The mixed-DNA blood

If you could puncture that evidenc... (read more)

0komponisto12y

That's a problem that would presumably exist to some extent on any public forum. I'm not too bothered by it myself; my feeling is that in such a situation one is not necessarily obliged to reply to all comments individually. Here's my suggestion: why don't we try it here first, and see how it works? I'd be interested to see if this kind of thing can work on LW. There probably won't be as many comments now as before, since it isn't a new topic. If it does get unwieldy, we can always move somewhere else. Rather than the Micheli report (which was the first-level ruling in the Guede case), you'd presumably be better off with the Massei-Cristiani report, which was actually about the Knox-Sollecito case (and is even available in translation by the PMF [http://perugiamurderfile.org] people). Interestingly, I agree with you that the knife and bra clasp are the strongest pieces of prosecution evidence (though I would have put them in the reverse order). However, they've been pretty severely punctured by Conti and Vecchiotti in their report. You can read the conclusions of that report here [http://knoxdnareport.wordpress.com/contents/conclusions-2/]. Anyway, I'll create a new Discussion thread upon confirmation that that's acceptable to you.

Making an Amanda Knox prediction market

rolf_nelson12y4

Dang, civil-case reversal rates are much higher than the U.S. (http://scholar.google.com/scholar?cluster=11027117874758072323), I still can't find anything on criminal cases though. komponisto said about 1/3, any cite on that?

There's lots of interesting high-profile Italian murders on Wikipedia, but after excluding those related to the mafia, terrorism, or serial-killers, there's not much recent activity left. Still, three of the ones I found (the Cogne homicide, the Novi Ligure murder, and the "Beasts of Satan") were partially or fully upheld, a... (read more)

0komponisto12y

It was a remark by Amanda Knox's attorney, Luciano Ghirga. I can't remember where offhand. One would expect the rate to be much higher than in the U.S. simply due to the rules of the game: unlike the U.S., Italian courts at the first level of appeal are allowed to reexamine the facts of the case, instead of merely ruling on whether procedure was correctly followed.

Making an Amanda Knox prediction market

rolf_nelson12y2

So, komponisto, Kevin, Pavitra, or anyone else, any general thoughts on how to calculate p(K | guilt) or p(K | innocence)? (K meaning Kevin's claim, that Knox will be released on appeal).

0komponisto12y

Elsewhere [http://www.injusticeinperugiaforum.org/post12811.html#p12811], I described my reasoning on p(K | innocence) as follows:

Making an Amanda Knox prediction market

rolf_nelson12y4

Hey Kevin, thanks for pinging me, sounds exciting. I'd bet Knox's odds are only somewhat better than the average guilty defendant of release on appeal, that "somewhat better" based on her having a more expensive legal and PR team than the average defendant. Can't find such info easily though, I'll google around tonight. Wikipedia says we're still on the first of the two mandatory appeals, do you mean released on the first appeal or on any appeal? What if it's remanded back to the lower court? Also, I assume you mean 'released on the murder charge... (read more)

0komponisto12y

My PredictionBook prediction [http://predictionbook.com/predictions/1804] was for the current (first) appeal (I specified "appeals court in Perugia"; the second appeal takes place in Rome). I agree. Although there should be at least some correlation between court verdicts and reality, a LW-style discussion would be much richer in information content.

Making an Amanda Knox prediction market

rolf_nelson12y0

[This comment is no longer endorsed by its author]Reply

Open Thread: May 2010

rolf_nelson13y2

I agree that AI deterrence will necessarily fail if:

All AI's modify themselves to ignore threats from all agents (including ones it considers irrational), and
any deterrence simulation counts as a threat.

Why do you believe that both or either of these statements are true? Do you have some concrete definition of 'threat' in mind?

0cousin_it13y

I don't believe statement 1 and don't see why it's required. After all, we are quite rational, and so is our future FAI.

Debunking komponisto on Amanda Knox (long)

rolf_nelson13y2

Matt wrote:

Here's a source for the 'three unidentified individuals' DNA' claim:

Thanks Matt. While my claim that there are not three unidentified individuals' DNA on the strap is tangential to C1, I will back it up anyway.

The Daily Mail is a tabloid, rather than a reliable source (in case the headline, 'The troubling doubts over Foxy Knoxy's role in Meredith Kercher's murder', didn't give it away) that clearly got the content for the summary article from Wikipedia. In contrast, the more reliable Sunday Times states instead that Meredith's, Rudy's, and R... (read more)

Debunking komponisto on Amanda Knox (long)

[+]rolf_nelson13y-5

Eliezer Yudkowsky13y17

Teaching requires empathy. A small application of empathy should tell you that no one in your audience will take your word for granted on this. This lack of trust could be very easily remedied with a single example: "cannot be dismissed as easily as you believe, because of some refuting point that wasn't brought up in any of the previous discussions, as you will also see wasn't brought up in any previous discussions".

I honestly don't see any valid reason to wait for a debate with komponisto in particular to provide this sort of evidence, either; which makes it sound suspiciously like an excuse for delay.

9mattnewport13y

I think that is highly unlikely. Nothing you presented in your post here was new information to me (or to anyone else who spent some time reading the original comment threads and did some research of their own I imagine). I'm familiar enough with it to know where you've been misleading or selective. Unless you have some secret new previously undisclosed information to reveal in your debate I rate the probability of me changing my estimates for Knox's guilt significantly as pretty low. Have you updated your own probabilities in light of the widespread disagreement with your position here? If so how?

Debunking komponisto on Amanda Knox (long)

rolf_nelson13y2

Again, empirically, ":s/Knox is guilty/Knox is innocent/g" helps even more.

Unless people think that "voting up comments you agree with and voting down things you disagree with" only happens on other sites, in which case I'm curious by what mechanism you think this is enforced on this site.

2wedrifid13y

The dynamic you mention is certainly present (and, there is some benefit to allowing disagreement at least a partial influence on votes). Unfortunately, in this instance it is hard to distinguish simple disagreement from disapproval of bad arguments and prvalent logical rudeness [http://lesswrong.com/lw/1p1/logical_rudeness/]. The same people who disagree with Knox being guilty are people who object to the type of reasoning used to support this contention. That's part of how they became convinced of her innocence in the first place.

7Eliezer Yudkowsky13y

It'd help if you picked a group belief that's actually demonstrably wrong to illustrate this, but you picked a hella wrong target this time around. Did you read through ~700 or so comments on the other Knox posts, or only the original posts?

Debunking komponisto on Amanda Knox (long)

rolf_nelson13y1

Jonathan, 'most people' (even on this site) did not reply to komponisto's post. To be fair to the site, I would not yet conclude for certain that a majority of the people on this site came to the wrong conclusion, given we don't actually know what a majority of the people on this site concluded.

Also, I specifically cherry-picked this as the sole issue (out of hundreds) that the LW community seems the most wrong about, so that skews things as well. I don't think the komponisto fiasco should reflect too poorly on LW as a whole.

0Jonathan_Graehl13y

I was talking about people who posted an opinion as to the probable guilt of the accused. While I think the first few such posts clearly had done the work of traversing the pro- anti- and wikipedia sites suggested, many later comments were based primarily on the evidence selected by previous players. I could be completely wrong about that, but that's how I felt: not motivated to filter through "the internet" for evidence, but interested in the discussion, and allowing myself to update based on facts brought to my attention by others. I do believe that "most people" (hopefully not here) really can't be trusted to have actually thought things through, though.

Debunking komponisto on Amanda Knox (long)

rolf_nelson13y2

As always, feel free to share your opinion on the matter.

Paul Crowley13y11

This response doesn't really suggest that you're taking your own responsibilities seriously in this matter.

The specifics here are interesting, but there's a more general point. If your interaction with a community isn't productive, there is simply no point in bemoaning the failings of the community and then carrying on as before. No matter what failings the community might or might not have, the only actions you directly decide are your own, and the only options that make sense are to give up and leave, or to figure out what action you can take to bring ... (read more)

Eliezer Yudkowsky13y11

Example problem: You stepped into a giant past discussion and didn't refer to it. If, for each point, you had either pointed to and refuted previous comments about those points, or else said, "And I read through the comments and found no reference to this point", you would have been picking up the conversation where it left off. As it is, the reaction is more like, "Oh, same points being rehashed again and ignoring the previous conversation we had about it." This reaction was sufficiently severe that no one bothered to talk about yo... (read more)

jimrandomh13y27

In the title, you named an opponent. You lost most of us right there, because debating against a person and searching for truth are incompatible mindsets. Since you tried to turn it into a status competition, we can't treat anything you say on the subject as trustworthy; you're too likely to deceive yourself and pass misconceptions on to us.

Debunking komponisto on Amanda Knox (long)

rolf_nelson13y-2

If you believe my claim C1 is false, I look forward to hearing your arguments about it. I still have not heard any rebuttal of my claim C1!

If you feel you have been logically insulted, explaining to me why you believe C1 is false would be a good option.

I agree with you only that your POV is popular on this topic on this site and mine is not; I knew that going in.

Debunking komponisto on Amanda Knox (long)

rolf_nelson13y9

War in Iran by 2016 might be a possible candidate.

1wedrifid13y

Sounds like a good one. But I expect you to have a better estimate than I do on that topic so I'm not going to bet against you!

Debunking komponisto on Amanda Knox (long)

rolf_nelson13y4

I completely agree with you that surrounding my statements with self-doubt would have increased my karma.

However, I do not agree that this is a sufficient reason to surround my statements with self-doubt. As I said, I don't care about karma.

I do care about things that often correlate with karma, such as accuracy and insight. If there is evidence that surrounding these statements with self-doubt will increase my accuracy, I will do it. Therefore, I look forward to any evidence proffered that my claim C1 is incorrect (such as an argument that one of komponisto's four statements I've charged to be misleading is, in fact, correct). So far, I have not heard any such evidence in this thread.

Debunking komponisto on Amanda Knox (long)

rolf_nelson13y4

Try to look at the current voting pattern on the comments to "Amanda Knox Test" and tell me there's not a correlation between favoring Knox's innocence and getting upvoted. (Don't forget to load all the comments so you see the people who are negative despite making reasoned comments about the case.)

Debunking komponisto on Amanda Knox (long)

rolf_nelson13y-2

Ah, but we know from the general pattern of votes (both for posts and for comments) that a certain subset of people on this forum do want to read posts and comments implying Knox is innocent, but do not want to read posts and comments implying Knox is guilty.

By your logic, does that mean you're advocating that only people who believe Knox is innocent should post, and that people who believe Knox is guilty should not post?

3Paul Crowley13y

If that's the only explanation you can think of for the pattern of voting you see, you're not ready to post here. Remember, few here give a damn about the case one way or the other, except as an example for training our brains. EDIT: since you're an SIAI donor, I'll cut you a little more slack than I did here, as per Wei Dai's comment.

Debunking komponisto on Amanda Knox (long)

rolf_nelson13y2

Would you have preferred that neither my post nor komponisto's "the amanda knox test" were top-level posts, but that we had just both posted them as comments to the original "You Be The Jury" post?

6Douglas_Knight13y

I would like to know your answers to my questions unaffected by my commentary.

Debunking komponisto on Amanda Knox (long)

[+]rolf_nelson13y-20

5Kevin13y

"Someone is wrong on the internet"[1] is not usually considered a claim that in and of itself deserves a response. If you're willing to remove C1 from your argument and defend any of the other claims, this post will probably get back up into positive karma. [1] http://xkcd.com/386/ [http://xkcd.com/386/]

Debunking komponisto on Amanda Knox (long)

rolf_nelson13y1

So edited, though I would have thought it obvious.

3Kevin13y

If you post here more often, you'll learn that certain linguistic patterns are required for the community to not get annoyed at you when making strong-sounding conclusions. Try not to take it too seriously. One regular poster here is a current theist. He has a lot of karma because he surrounds many of his statements in self-doubt.

Debunking komponisto on Amanda Knox (long)

rolf_nelson13y2

If your thesis is that debunking the content of a featured post in this forum, is not on-topic for this forum, then I personally disagree. If someone posts false information as a featured post, then I personally would prefer to be informed that it is false rather than continue believing false information. There are probably other readers who feel the same, and I hope this post provided such a service to them.

3wedrifid13y

It is not. I take Vive's thesis [http://lesswrong.com/lw/1pc/debunking_komponisto_on_amanda_knox_long/1jx5?context=1#1jx5] as granted and assume it is obvious to most readers. My own contention is that this post should not have been made and should not have been able to be posted by a user with no karma.

Debunking komponisto on Amanda Knox (long)

rolf_nelson13y10

Sounds reasonable. I wonder if there should be more survey style posts then, but on topics that will have verifiable outcomes. For example, one could pick out a topic from one of the prediction markets and discuss that. This would have the advantage that, at the end of the day, if someone come to the wrong conclusion, they would eventually realize they came to the wrong conclusion and have an opportunity to learn something from the exercise.

1wedrifid13y

I totally agree (and made a similar suggestion in the recent games [http://lesswrong.com/lw/1ov/play_for_a_cause/] thread.)

Debunking komponisto on Amanda Knox (long)

[+]rolf_nelson13y-5

0Jack13y

I'm shocked and dismayed that anyone went back and downvoted koponisto's post, which is probably the best discussion we've ever had here.

7wedrifid13y

I believe already have, primarily because it encouraged an influx of posters only interested in political advocacy of one kind of another. It significantly lowered the quality of conversation for some time.. I did, however, upvote Komponisto's earlier survey style post, which was an excellent exercise in rationality.

Debunking komponisto on Amanda Knox (long)

rolf_nelson13y-3

I don't really care about karma. If someone isn't interested in reading about it, then they shouldn't read it.

Paul Crowley13y10

If lots of people aren't interested in reading it, as reflected in karma scores, then you should find somewhere to post it where people do want to read it.

6AnnaSalamon13y

Rolf, even if you don't care about karma, it might be good practice to keep LW visibly about rationality, and so to briefly recap the relevance of this post to LW and rationality (via its history with komposito's post), rather than have it appear that Amanda Knox or other current events are interesting here in their own right. Though I understand if you don't have time.

8wedrifid13y

You also haven't cared to make any contribution on the topic of rationality. The karma system serves to prevent new posters posting Mind Killing [http://lesswrong.com/lw/gw/politics_is_the_mindkiller/] Advocacy [http://lesswrong.com/lw/r3/against_devils_advocacy/]. I do not understand why that process did not work in this instance. I count few posts of yours that have not been either in the Knox thread or dragging the Knox issue to other parts of the site by criticizing Komponisto. The system, if working as advertised, would not have allowed this post.

Debunking komponisto on Amanda Knox (long)

rolf_nelson13y0

Note: this is a post version of the same document that I posted yesterday.

Open Thread: February 2010

rolf_nelson13y-1

(a supposed handprint of Knox's on a pillow in Kercher's room) is an outright falsehood -- as you will see from following Nelson's link, it's not even (close to) what that article claims.

Did you misread the source?

I said:

"One of Amanda's bloody footprints was found inside the murder room, on a pillow hidden under Meredith's body."

The source I cited (http://abcnews.go.com/TheLaw/International/story?id=7538538&page=2) said:

"Guede's bloody shoeprint was also positively identified on a pillow found under the victim's body... Police also f... (read more)

The Amanda Knox Test: How an Hour on the Internet Beats a Year in the Courtroom

rolf_nelson13y-2

Point-by-point:

Given that AK's roommate is dead, a break-in was staged, and the coroner's report showed multiple attackers, the prior on AK being a murderer of Meredith is rather high. On the other hand, if we throw away all known evidence, the prior of AK (or Guede, for that matter) being a murderer of Meredith is less than one in a trillion. I claim the former approach, where you use evidence rather than ignore it when it's inconvenient, is preferable. [Edit: OK, that was too snarky. Let me instead say that you should start with a tighter prior rather th... (read more)

Jack13y12

My ADHD brain lost interest in this after the huge discussion here covered pretty much everything having to do with the trial. And komponisto knows this stuff way better than I do so I'll let him respond. But nearly all of the regulars here looked at the exact same evidence you are bringing up now and nearly all of us eventually concluded that it was more likely than not that AK was innocent. Moreover, I specifically recall discussions of every single point you bring up and I believe every single one was resolved. So you might want to look back at the comm... (read more)

Open Thread: February 2010

rolf_nelson13y-2

Re: dark arts territory, I agree completely. This criticism should be directed more strongly to komponisto. My intent here is merely to repair some of the Bayesian damage caused by komponisto's original post. Perhaps this will dissuade people from wandering into dark arts territory in the future, or at least to wander in with misleading claims.

8Vive-ut-Vivas13y

I hardly think komponisto inflicted "Bayesian damage" on the members of Less Wrong, seeing as they had already overwhelmingly come to the conclusion that Amanda Knox was not guilty [http://lesswrong.com/lw/1ir/you_be_the_jury_survey_on_a_current_event/] before he had even presented his own arguments.

Open Thread: February 2010

rolf_nelson13y-2

I said once in the doc that 'truejustice claims that X'. Because I said 'truejustice claims that X' rather than just stating X as though it were uncontested fact, and because X is basically correct, I claim that my doc is not misleading. If X is untrue, that would be a different story. In other words, if komponisto cited FoA and FoA's claims were true, I would not accuse him of being misleading.

Open Thread: February 2010

rolf_nelson13y6

I've created a rebuttal to komponisto's misleading Amanda Knox post, but don't have enough karma to create my own top-level post. For now, I've just put it here:

http://docs.google.com/View?id=dgb3jmh2_5hj95vzgk

7wedrifid13y

I don't understand how this was worked around. It looks like (rolf's karma + karma lost by this being posted at the top level) would still have been insufficient. The karma limit was serving the purpose for which it was intended. If, for some reason, an exception was granted I would like to see this announced.

4Vive-ut-Vivas13y

Criticizing komponisto for citing "Friends of Amanda Knox" while you yourself cite "True Justice" causes those criticisms to fall flat. Unfortunately, I find that your essay is wading into Dark Arts territory, since its intent is to show that komponisto's original essay was "misleading", and that that would somehow give veracity to arguments of Amanda Knox's guilt. Using that same logic, one would have to consider the implications of the chief prosecutor in Amanda Knox's case being convicted of abuse of office [http://www.washingtonpost.com/wp-dyn/content/article/2010/01/22/AR2010012203022.html] in another murder trial. However, I would be interested in seeing komponisto and rolf nelson discuss the actual details of the case; in particular, the points that rolf nelson brought up in the essay.

komponisto13y10

If you actually want to debate this, we could do so in the comments section of my post, or alternatively over in the Richard Dawkins forum.

(Though since you say "my intent is merely to debunk komponisto's post rather than establish Amanda's guilt", I'm suspicious. See Against Devil's Advocacy.)

Make sure you've read my comments here in addition to my post itself.

There is one thing I agree with you about, and that is that this statement of mine

these two things constituting so far as I know the entirety of the physical "evidence" agains

rolf_nelson13y0

Under Robin’s approach to value uncertainty, we would (I presume) combine these two utility functions into one linearly

It's also not clear which affine transformations of EU1 and EU2 should be considered relevant. If the question of 'what fraction of achievable utility will we get?' plays a consideration (for example, as part of a strategy to bound your utility function to avoid pascal's mugging), then EU2 will get squashed more than EU1.

Easy Predictor Tests

rolf_nelson13y0

Cool idea. If there were an easy way to hide the scores on comments, you could wait a week to make the predictions and then immediately see if your predictions are correct. This would reduce the interval between making the prediction and seeing if it's correct, which presumably would provide better training and feedback.