some Etas estimated to be around 2 or 3, but since I am fitting a quite noisy PD data, I think they are actually reasonable no Etas close to 0 cov% esimated in the range of 10-90%.should those small ones like 10% be taken out?
________________________________ From: "Bachman, William" <william.bach...@iconplc.com> To: Ethan Wu <ethan.w...@yahoo.com>; nmusers@globomaxnm.com Sent: Wednesday, April 15, 2009 12:12:56 PM Subject: RE: [NMusers] OMEGA selection Well, the first thing that I would do is look at the magnitude of the estimates of the etas. I would eliminate those etas that are poorly estimated (essentially the very large values or those approaching zero). ________________________________ From: owner-nmus...@globomaxnm.com [mailto:owner-nmus...@globomaxnm.com] On Behalf Of Ethan Wu Sent: Wednesday, April 15, 2009 11:47 AM To: nmusers@globomaxnm.com Subject: [NMusers] OMEGA selection Dear all, I am fitting a PD response, and the equation goes like this: total response = baseline+f(placebo response) +f(drug response) first, I tried full omega block, and model was able to converge, but $COV stop failed. To me, this indicates that too many parameters in the model. The structure model is rather simple one, so I think probably too many Etas. I wonder is there a good principle of Eta reduction that I could implement here. Any good reference? ICON plc made the following annotations. ------------------------------------------------------------------------------ This e-mail transmission may contain confidential or legally privileged information that is intended only for the individual or entity named in the e-mail address. If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution, or reliance upon the contents of this e-mail is strictly prohibited. If you have received this e-mail transmission in error, please reply to the sender, so that ICON plc can arrange for proper delivery, and then please delete the message. Thank You, ICON plc South County Business Park Leopardstown Dublin 18 Ireland Registered number: 145835
