-------- Original Message -------- Subject: MorphoJ bug warning: pooled within-group regression Date: Wed, 24 Feb 2010 03:55:41 -0500 From: Chris Klingenberg <[email protected]> Reply-To: [email protected] Organization: University of Manchester To: [email protected] Dear morphometricians I have just become aware of a programming bug in the computations for the residuals from pooled within-group regression (Regression procedure, with option for 'Pooled regression within subgroups' selected). The mistake affects only the computation of residuals. Depending on the directions of the regression vector and the differences between groups, this bug tends to exaggerate group differences. This effect is large in some of the examples I've tried. This is especially important when the pooled within-group regression is used for size correction in several groups simultaneously. The results obtained in this way with the existing versions of MorphoJ (all 1.00 and 1.01 versions) should be considered as unreliable and possibly misleading. I sincerely apologize to all those of you who are affected by this problem. I am putting the finishing touches on a new version (1.02a), which will include a correction of the bug. I will make another announcement to Morphmet when I upload the new version to my lab web site. Best wishes, Chris (P.S.: Andrea Cardini will -- *************************************************************** Christian Peter Klingenberg Faculty of Life Sciences The University of Manchester Michael Smith Building Oxford Road Manchester M13 9PT United Kingdom Telephone: +44 161 275 3899 Fax: +44 161 275 5082 E-mail: [email protected] Web: http://www.flywings.org.uk Skype: chris_klingenberg *************************************************************** -- For now, new message AND replies should be sent to: [email protected] /* Replies will be sent to the list. */ For more information visit http://www.morphometrics.org
