tag:blogger.com,1999:blog-16612221.post459450171120691667..comments2024-03-19T03:14:04.172-04:00Comments on Rabett Run: Wisdom from USENETEliRabetthttp://www.blogger.com/profile/07957002964638398767noreply@blogger.comBlogger14125tag:blogger.com,1999:blog-16612221.post-45389567821744076152009-11-17T09:39:04.942-05:002009-11-17T09:39:04.942-05:00nit:
broken link in the original post above should...nit:<br />broken link in the original post above should go to something about Tol and the others: http://sadielou.files.wordpress.com/2008/10/wp252.pdfHank Robertshttps://www.blogger.com/profile/07521410755553979665noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-1003927704092115252009-02-18T05:41:00.000-05:002009-02-18T05:41:00.000-05:00Eli, thanks for bringing this up.I've done alot of...Eli, thanks for bringing this up.<BR/><BR/>I've done <A HREF="http://mises.org/Community/blogs/tokyotom/search.aspx?q=weitzman" REL="nofollow">alot of commenting on Weitzman</A>, BTW, including posting a working draft of his response to Nordhaus' criticisms.TokyoTomhttps://www.blogger.com/profile/09588387872596983852noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-53739392228253917042009-01-15T17:41:00.000-05:002009-01-15T17:41:00.000-05:00An anonymous up there says, the basic idea is not ...An anonymous up there says, the basic idea is not novel, the contribution of the economists is not the idea itself but rather the quantitative application to climate change (with numbers that stand up to peer review even if they are not unimpeachable).James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-15598752934145028822009-01-13T14:15:00.000-05:002009-01-13T14:15:00.000-05:00Anon 9:31 said"those are only opinions, not facts....Anon 9:31 said<BR/>"those are only opinions, not facts."<BR/><BR/>That's precisely the point.<BR/><BR/>"Expectation" does not deal with facts. It deals with the future -- ie, with potentialities.<BR/><BR/>Arguably, it is the best way to deal with uncertain risks/costs because it figures in the possibility of high cost/low probability events without knowing whether they will occur or not.<BR/><BR/>Sometimes "opinions" ("guesses", "hunches") are actually better than "facts".Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-88454452011334223642009-01-12T12:31:00.000-05:002009-01-12T12:31:00.000-05:00Nice thought-provoking post, but those are only op...Nice thought-provoking post, but those are only opinions, not facts.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-84549090605403877342009-01-12T12:15:00.000-05:002009-01-12T12:15:00.000-05:00The insurance industry has been using "expectation...The insurance industry has been using "expectation" forever to set rates.<BR/><BR/>it's common is science as well (especially physics).<BR/><BR/>And gamblers have been using it since Pacal.<BR/><BR/>So it is more than a little surprising that some consider it a "novel" idea (and even more surprising that many apparently are not even aware of it's existence)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-37756339830087112582009-01-12T01:40:00.000-05:002009-01-12T01:40:00.000-05:00Here's the thread:http://preview.tinyurl.com/7qfq9...Here's the thread:<BR/><BR/>http://preview.tinyurl.com/7qfq9l<BR/><BR/>No sign of Lydick on this thread (I believe he had already passed on), but some interesting replies from John McCarthy. It's been a long time since we've seen such cogent opposition.<BR/><BR/>I clarify further down:<BR/><BR/>"If you ask well-informed people not about their best estimate<BR/>but their 95 % confidence estimate of best and worst cases, I believe that you will find a severe asymmetry. 5 % is not such a small risk as to be<BR/>negligible. "<BR/><BR/>It's interesting to see how McCarthy and I came to a sort of agreement in the discussion. Those were the days... Hard to believe it was only 9 years ago.Michael Tobishttps://www.blogger.com/profile/08229460438349093944noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-40327293336319137342009-01-12T01:29:00.000-05:002009-01-12T01:29:00.000-05:00Thanks, Eli. Actually Carl has picked an actual ni...Thanks, Eli. <BR/><BR/>Actually Carl has picked an actual nit, although I can't imagine where the -10 comes from. Had he accused me of concluding -5, it would be literally consistent with what I said. <BR/><BR/>(Is this Lydick's ghost? I thought he had left us lo these many years.)<BR/><BR/>Of course, in Carl's scenario, I conclude the utterly conventional 0.99 * +2 + 0.01 * -5 = +1.93; while<BR/>the quoted statement pretty clearly advocates -5.<BR/><BR/>Here's what I should have said. The costs are distributed in an asymmetric fashion over the probablities. The 1 sigma benign probably case does not, by now, benefit us at all, but even if it does it clearly doesn't match the damage due to the 1 sigma problematic case. And at 2 sigma benign, the benefits are hardly better at all, while the damages are even worse. <BR/><BR/>My argument does depend on some conclusions about the shape of the cost function which . It's not an extravagant claim, and while a case for it is built up in points 3, 4, and 5, I would agree that it remains implicit, and the argument would thus stand up better with a little more refinement.<BR/><BR/>Thanks for the correction.Michael Tobishttps://www.blogger.com/profile/08229460438349093944noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-79659463521849970102009-01-12T01:28:00.000-05:002009-01-12T01:28:00.000-05:00Sorry, -10 is supposed to be -5. But you get my p...Sorry, -10 is supposed to be -5. But you get my point. Gravityloss says it better than me.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-17460596532867956312009-01-11T23:50:00.000-05:002009-01-11T23:50:00.000-05:00Check your math, even better, check your drinkCheck your math, even better, check your drinkEliRabetthttps://www.blogger.com/profile/07957002964638398767noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-26880046380167732102009-01-11T22:59:00.000-05:002009-01-11T22:59:00.000-05:00"6) The risk-weighted cost of unrestrained anthrop..."6) The risk-weighted cost of unrestrained anthropogenic perturbation must therefore be dominated by the fact that the plausible worst cases have more cost than the plausible best cases have benefit."<BR/><BR/>By this logic, in a circumstance with a 99% outcome of +2 units, and a 1% outcome of -5 units, the correct policy would be to brace for the -10 outcome.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-20578108751891943452009-01-11T11:41:00.000-05:002009-01-11T11:41:00.000-05:00Everyone (that should be all engineers and most sc...Everyone (that should be all engineers and most scientists at least) who has calculated an expected value E(f) of function f(x) where x has a probability distribution understands that you can't just automatically* use the average x (let's mark it as _x_) and calculate the function at that point f(_x_) and use that as the expected value.<BR/><BR/>i.e.<BR/>E(f(x)) is not always f(E(x))<BR/><BR/>Even if RPJr does it.<BR/><BR/>You have to integrate and weigh over all the probabilities:<BR/>E(f) = int(p(x)*f(x)) over the whole space of x.<BR/><BR/>It is interesting how such basic things are "news" for economists and policy analysts etc...<BR/><BR/>But Michael, your other things in that post show some interesting thoughts as well. <BR/><BR/>Like the asymmetry that there can be bad local effects even if global temperature doesn't rise, but there won't be local neutral effects if the global rises. Ie in a four field, only one corner is neutral and the rest are bad. (Or one corner is impossible, global change but local statism.)<BR/><BR/><BR/>Meanwhile, James Annan has some good discussion on why the very very small probabilities of huge effects should not weigh in too much on policy, ie they are a mathematical artefact. That the real climate sensitivity is a property of nature that exists, not something fundamentally unpredictable.<BR/><BR/>*: in some cases you can use the average x to calculate the average f(x), but often those assumptions don't hold.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-3875491415701340432009-01-11T06:56:00.000-05:002009-01-11T06:56:00.000-05:00"USENET has an extremely deserved reputation...."N..."USENET has an extremely deserved reputation...."<BR/><BR/>Not if you went down well-self-regulated groups such as "sci.*", "comp.*" (an even "alt.comp.*"). The nastier types were denizens of the "alt.sex.*" tree and left us alone. It was a place most of us trusted personal information. Opening it up outside mainly academia, government, and IT companies led to the much more hostile environment of the modern era.<BR/><BR/>(And we took our revenge on spammers by mail-bombing their accounts, and blacklisting them).Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-23505784619451553022009-01-11T03:23:00.000-05:002009-01-11T03:23:00.000-05:00Many thanks Eli. My career is in such a marginal s...Many thanks Eli. <BR/><BR/>My career is in such a marginal state that it in some sense hardly matters what I get cited for. But I did say these things long before Weitzman, publicly and often. <BR/><BR/>This particular effort that you quote seems a bit longwinded and stuffy. I think I was trying hard to be unambiguous. I hope my writing is a but more attractive nowadays. The effort at non-ambiguity may help establish that I was all over these ideas a decade ago.<BR/><BR/>I simply didn't think it was a deep enough idea to be worthy of submission for peer review. One of many tactical errors, I see. One of many lessons learned too late to be of any advantage.<BR/><BR/>Anyway, many thanks indeed for standing up for me on this matter and thanks for digging up a good example.<BR/><BR/>mtMichael Tobishttps://www.blogger.com/profile/08229460438349093944noreply@blogger.com