Comments on: Quote of the Week, June 12, 2007 http://hea-www.harvard.edu/AstroStat/slog/2007/quote-of-the-week-june-12-2007/ Weaving together Astronomy+Statistics+Computer Science+Engineering+Intrumentation, far beyond the growing borders Fri, 01 Jun 2012 18:47:52 +0000 hourly 1 http://wordpress.org/?v=3.4 By: vlk http://hea-www.harvard.edu/AstroStat/slog/2007/quote-of-the-week-june-12-2007/comment-page-1/#comment-24 vlk Thu, 14 Jun 2007 01:10:31 +0000 http://hea-www.harvard.edu/AstroStat/slog/2007/quote-of-the-week-june-12-2007/#comment-24 Yes, agree completely, and in fact it reinforces the point I was <a href="http://hea-www.harvard.edu/AstroStat/slog/2007/on-the-unreliability-of-fitting/" rel="nofollow">trying to make</a>, which is that blind assembly-line fitting runs on large numbers of datasets carried out without human supervision are all highly suspect. Even something as simple as <a href="http://hea-www.harvard.edu/AstroStat/BEHR/" rel="nofollow">BEHR</a> runs into trouble finding the right confidence interval for the fractional hardness ratio HR -- it has a W-shaped posterior when the counts are low and the prior is aggressively non-informative, and tends to catch the edges of the range than the central bump. Yes, agree completely, and in fact it reinforces the point I was trying to make, which is that blind assembly-line fitting runs on large numbers of datasets carried out without human supervision are all highly suspect.

Even something as simple as BEHR runs into trouble finding the right confidence interval for the fractional hardness ratio HR — it has a W-shaped posterior when the counts are low and the prior is aggressively non-informative, and tends to catch the edges of the range than the central bump.

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By: aconnors http://hea-www.harvard.edu/AstroStat/slog/2007/quote-of-the-week-june-12-2007/comment-page-1/#comment-22 aconnors Wed, 13 Jun 2007 21:58:49 +0000 http://hea-www.harvard.edu/AstroStat/slog/2007/quote-of-the-week-june-12-2007/#comment-22 This quote is actually a comment on VLK's May 25th post, "On the Unreliability of Fitting". It seems to me that Xiao Li is telling us that MCMC methods are not a panacea for "fitting" (i.e. finding the modes and mapping out uncertainties) in multi-modal spaces. Considerable care must still be taken to make sure one covers the difficult parameter/probability space. This quote is actually a comment on VLK’s May 25th post, “On the Unreliability of Fitting”.
It seems to me that Xiao Li is telling us that MCMC methods are not a panacea for “fitting” (i.e. finding the modes and mapping out uncertainties) in multi-modal spaces. Considerable care must still be taken to make sure one covers the difficult parameter/probability space.

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