RE: WRES AND OUTLIER IDENTIFICATION/EXCLUSION

From: "Elassaiss - Schaap, J. (Jeroen)" jeroen.elassaiss@organon.com Subject: RE: [NMusers] WRES AND OUTLIER IDENTIFICATION/EXCLUSION Date: Thu, 28 Sep 2006 08:18:30 +0200 Hi Ken, To my opinion your idea of flagging with an extra epsilon is a first step towards complete iterative weighting as demonstrated by Jan Freijer, see http://www.page-meeting.org/page/page2005/PAGE2005P76.pdf (I guess he won't chime in himself). His implementation has two pros: i) it is unsupervised and ii) it is gradual. He specified the example of errors in dosing and sampling time, but the approach seems general and therefore also applicable to other causes of outliers. I have used a similar approach during my PhD but in another field with smoothing rather than fitting, i.e. adaptive smoothing. It worked really well in removal of (electronic) artifacts observed in noisy, densily sampled time series and was simple to implement (iteration on a linear regression). Best regards, Jeroen J. Elassaiss-Schaap Scientist PK/PD Organon NV PO Box 20, 5340 BH Oss, Netherlands Phone: + 31 412 66 9320 Fax: + 31 412 66 2506 e-mail: jeroen.elassaiss@organon.com