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[OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer

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(2014-Aug-21, 22:57:35)Duxide Wrote: However something I never liked about twin model fitting is a practice that is universally accepted: the most parsimonious model is always chosen also when it shows a worse fit to the data, as long as this is not significantly worse. So it's ok if it doesn't fit the data as well as the other, more parsimonious model unless the degeneration in fit is not significant. No appeals to theory or previous research is needed, the principle that fewer parameters are better is sufficient to reject a model with more of them (e.g. AE would be preferred over ACE even if the latter fits the data better but not significantly so).


I completely agree with that. Especially since they use Chi-square, very sensitive to sample size. I have elsewhere noted this for the article of van Soelen (2011) where given their table 5 they say that PIQ h2 does not increase with age. The thing is that in childhood the selected model was AE due to C parameter non significant (and yet was non-trivial in magnitude = 0.17). I also said that when you drop one such parameter, the variance of the removed parameter will be given to either A or C (depending on which one is removed) because the total must be 100. Thus, they remove C and its variance is given to A, which becomes inflated. This is ridiculous. I even remembered the appendix of Behavioral Genetics (6th edition, by Plomin) where Shaun Purcell said explicitly that in principle we do not want the full model (ACE) because it's a null model (everything is estimated, no constraint imposed). Thus, the rationale is to test the full (or null) model against the reduced models. I was shocked when reading this.

(2014-Aug-21, 23:45:22)Dalliard Wrote: Let's say rMZ is 0.8 and rDZ is 0.3 (and there is no AM). This could be because there's D variance and no C variance. But it could as well be that there's both D and C variance but more D. In the classic twin design, C and D are confounded; they cannot be simultaneously estimated because of underidentification. You need additional types of relatives to estimate both C and D.


I do not understand. What you seem to say is that we need twin + non twin data. But, in what is it a problem inherent to ADE model ?

(2014-Aug-21, 23:45:22)Dalliard Wrote: In IQ studies, rMZ is usually ≤2*rDZ, so models with D fit poorly and are not estimated. The model assumption that genetic variance is all A may be wrong, but that's what the data are usually consistent with.


I did not remember very well the C parameters for non white samples, so I looked at the paper again. I see that the C is non-trivial, so yes it makes sense.

For those who are interested, here's a good article i read some time ago :

Hill, W. G., Goddard, M. E., & Visscher, P. M. (2008). Data and Theory Point to Mainly Additive Genetic Variance for Complex Traits. PLoS Genetics, 4, e1000008.
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Messages In This Thread
[OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Chuck - 2014-Jul-14, 06:25:48
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Emil - 2014-Jul-14, 10:45:09
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Meng Hu - 2014-Jul-14, 19:57:08
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Chuck - 2014-Jul-19, 22:37:13
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Chuck - 2014-Aug-05, 22:39:40
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Emil - 2014-Aug-07, 19:25:59
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Chuck - 2014-Aug-07, 22:27:33
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Chuck - 2014-Aug-08, 00:32:10
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Chuck - 2014-Aug-19, 03:11:37
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Emil - 2014-Aug-08, 00:29:43
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Emil - 2014-Aug-19, 09:36:33
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Chuck - 2014-Aug-19, 19:22:42
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Duxide - 2014-Aug-19, 19:33:48
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Chuck - 2014-Aug-19, 20:27:44
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Duxide - 2014-Aug-19, 20:56:25
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Emil - 2014-Aug-19, 21:23:08
RE: Genetic and Environmental Determinants of IQ - by Meng Hu - 2014-Aug-21, 01:11:58
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Chuck - 2014-Aug-21, 01:25:25
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Meng Hu - 2014-Aug-21, 02:29:13
RE: Genetic and Environmental Determinants of IQ - by Dalliard - 2014-Aug-21, 19:58:04
RE: Genetic and Environmental Determinants of IQ - by Meng Hu - 2014-Aug-21, 21:11:34
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Chuck - 2014-Aug-21, 23:43:11
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Duxide - 2014-Aug-21, 22:57:35
RE: Genetic and Environmental Determinants of IQ - by Dalliard - 2014-Aug-21, 23:45:22
RE: Genetic and Environmental Determinants of IQ - by Meng Hu - 2014-Aug-22, 04:19:42
RE: Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Americans - by Chuck - 2014-Aug-22, 04:25:14
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Meng Hu - 2014-Sep-02, 23:40:26
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Chuck - 2014-Sep-03, 02:48:14
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Meng Hu - 2014-Sep-07, 01:49:42
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Chuck - 2014-Sep-07, 19:35:52
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Duxide - 2014-Sep-08, 13:02:31
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Chuck - 2014-Sep-08, 15:16:27
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Emil - 2014-Sep-07, 21:44:22
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Chuck - 2014-Sep-07, 23:34:54
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Emil - 2014-Sep-07, 23:51:24
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Meng Hu - 2014-Sep-08, 00:21:20
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Emil - 2014-Sep-08, 00:36:38
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Emil - 2014-Sep-08, 15:04:06
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Duxide - 2014-Sep-08, 17:48:27
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Duxide - 2014-Sep-08, 18:01:30
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Chuck - 2014-Sep-08, 19:44:52
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Duxide - 2014-Sep-08, 19:48:12
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Chuck - 2014-Sep-11, 23:19:01
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Duxide - 2014-Sep-12, 10:53:22
RE: [OBG] Genetic and Environmental Determinants of IQ - by Dalliard - 2014-Sep-09, 21:25:33
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Meng Hu - 2014-Sep-10, 01:12:35
RE: [OBG] Genetic and Environmental Determinants of IQ - by Dalliard - 2014-Sep-11, 18:27:00
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Emil - 2014-Sep-11, 23:29:03
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Chuck - 2014-Sep-11, 23:35:43
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Emil - 2014-Sep-11, 23:44:40
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Meng Hu - 2014-Sep-12, 01:30:14
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Emil - 2014-Sep-12, 02:26:19
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Duxide - 2014-Sep-12, 22:59:24
RE: [OBG] Genetic and Environmental Determinants of IQ in Black, White, and Hispanic Amer - by Chuck - 2014-Sep-14, 21:11:40
 
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