Comments on: HeartScan http://blog.sethroberts.net/2009/08/13/heartscan/ Personal Science, Self-Experimentation, Scientific Method Wed, 08 Feb 2012 23:02:17 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: anon http://blog.sethroberts.net/2009/08/13/heartscan/#comment-347411 anon Tue, 29 Sep 2009 15:34:13 +0000 http://www.blog.sethroberts.net/2009/08/13/heartscan/#comment-347411 Improve what, exactly? If you mean improving predictive ability in standard regression models, nothing says that the predictor has to be symmetric, or that prediction will be better/worse if you transform the predictor to be symmetric. Improve what, exactly? If you mean improving predictive ability in standard regression models, nothing says that the predictor has to be symmetric, or that prediction will be better/worse if you transform the predictor to be symmetric.

]]> By: seth http://blog.sethroberts.net/2009/08/13/heartscan/#comment-346408 seth Sat, 26 Sep 2009 11:14:56 +0000 http://www.blog.sethroberts.net/2009/08/13/heartscan/#comment-346408 So what if you don't get symmetry -- you'll get closer to symmetry. You'll improve the situation. So what if you don’t get symmetry — you’ll get closer to symmetry. You’ll improve the situation.

]]> By: anon http://blog.sethroberts.net/2009/08/13/heartscan/#comment-346328 anon Sat, 26 Sep 2009 03:59:59 +0000 http://www.blog.sethroberts.net/2009/08/13/heartscan/#comment-346328 Because of the way it's calculated (look up the Agatston Scoring method) CAC has a big spike of values at exactly zero - maybe 50% of the population. Transform away, but you're not going to get symmetry (and, for many statistical purposes, you don't need it) The scoring method certainly could be improved (and has been, by some statisticians) but Agatston remains the default. Moreover, there's reason to think that different biology may dictate people have some vs zero CAC, and lots vs not much. Because of the way it’s calculated (look up the Agatston Scoring method) CAC has a big spike of values at exactly zero – maybe 50% of the population. Transform away, but you’re not going to get symmetry (and, for many statistical purposes, you don’t need it)

The scoring method certainly could be improved (and has been, by some statisticians) but Agatston remains the default. Moreover, there’s reason to think that different biology may dictate people have some vs zero CAC, and lots vs not much.

]]> By: david http://blog.sethroberts.net/2009/08/13/heartscan/#comment-334632 david Thu, 20 Aug 2009 07:12:56 +0000 http://www.blog.sethroberts.net/2009/08/13/heartscan/#comment-334632 thnx thnx

]]> By: seth http://blog.sethroberts.net/2009/08/13/heartscan/#comment-334542 seth Wed, 19 Aug 2009 23:56:41 +0000 http://www.blog.sethroberts.net/2009/08/13/heartscan/#comment-334542 David, my HDL is low. The other stuff is okay. David, my HDL is low. The other stuff is okay.

]]> By: david http://blog.sethroberts.net/2009/08/13/heartscan/#comment-334433 david Wed, 19 Aug 2009 16:45:13 +0000 http://www.blog.sethroberts.net/2009/08/13/heartscan/#comment-334433 and seth, how have your blood lipids been over the years if you don't mind the question? and seth, how have your blood lipids been over the years if you don’t mind the question?

]]> By: david http://blog.sethroberts.net/2009/08/13/heartscan/#comment-334430 david Wed, 19 Aug 2009 16:38:04 +0000 http://www.blog.sethroberts.net/2009/08/13/heartscan/#comment-334430 peter, what is your diet and lifestyle history? Sound like you are doing some things right... peter, what is your diet and lifestyle history? Sound like you are doing some things right…

]]> By: Peter http://blog.sethroberts.net/2009/08/13/heartscan/#comment-333621 Peter Mon, 17 Aug 2009 17:28:21 +0000 http://www.blog.sethroberts.net/2009/08/13/heartscan/#comment-333621 My coronary calcium score was zero. I'm not sure what exactly that means. My coronary calcium score was zero. I’m not sure what exactly that means.

]]> By: seth http://blog.sethroberts.net/2009/08/13/heartscan/#comment-332507 seth Fri, 14 Aug 2009 11:49:26 +0000 http://www.blog.sethroberts.net/2009/08/13/heartscan/#comment-332507 JLD, I've changed the link. Try again. JLD, I’ve changed the link. Try again.

]]> By: JLD http://blog.sethroberts.net/2009/08/13/heartscan/#comment-332500 JLD Fri, 14 Aug 2009 11:03:50 +0000 http://www.blog.sethroberts.net/2009/08/13/heartscan/#comment-332500 <em>they should have transformed their data</em> Huh? This paper of yours isn't open access? So you really think that it is worth $ 31.50 (of which you receive <strong>zilch)</strong>)? I am going to revise the credibility of this blog... they should have transformed their data

Huh? This paper of yours isn’t open access? So you really think that it is worth $ 31.50 (of which you receive zilch))? I am going to revise the credibility of this blog…

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