1 / 7

Nov-2009

Nov-2009. A bias is a bias is a bias. By Dietmar Stöckl ST T Consulting. A bias …. VIM 4.20 (5.25)# instrumental bias = average of replicate indications minus a reference quantity value … is a bias is a bias http://en.wikipedia.org/wiki/Rose_is_a_rose_is_a_rose_is_a_rose

race
Download Presentation

Nov-2009

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Nov-2009 A bias is a bias is a bias By Dietmar Stöckl STT Consulting

  2. A bias … • VIM 4.20 (5.25)# • instrumental bias = • average of replicate indications • minus a reference quantity value • … is a bias is a bias • http://en.wikipedia.org/wiki/Rose_is_a_rose_is_a_rose_is_a_rose • #http://www.bipm.org/en/publications/guides/vim.html Tin Can 11 - A Bias is a Bias is a Bias

  3. Bias – Past & Present • There was (1) and there is (2) a tendency to put bias under the square root. • This was and this is wrong (3)! • This is NOT GUM! • When you HAVE a bias, TREAT it as a bias! • 1 Harris EK. Arch Pathol Lab Med 1988;112:416-20. • 2 http://www.westgard.com/rilibak-2.htm • 3 Thienpont LM. Clin Chem 2008;54:1587-8. Tin Can 11 - A Bias is a Bias is a Bias

  4. Treatment of bias • 4 possibilities • ─neglect it (when small) • ─correct it • ─report it • ─put it into total error calculations • (in principle, this is the same as "report it") Tin Can 11 - A Bias is a Bias is a Bias

  5. Bias & GUM# • GUM unequivocally states that bias has to be corrected. Only in EXCEPTIONAL cases (F.2.4.5), bias may be REPORTED, but not taken under the square root. • In principle, we then come to the same numbers as the total error concept, just the other way round: • TE = Bias + z x s; GUM = k x s + Bias. • The example given in GUM, however, does not exactly cover the situation in the clinical laboratory. Therefore, there always will be a point of discussion there. • #http://www.bipm.org/utils/common/documents/jcgm/JCGM_100_2008_E.pdf Tin Can 11 - A Bias is a Bias is a Bias

  6. Nature of bias & Consequences thereof • Bias is a location measure, it will offset your whole population. • If you fail to recognize that as analytical chemist, you will do a bad job. • Accreditation, regulation, are other things. • You should resist them when they ask you to do the wrong things. Tin Can 11 - A Bias is a Bias is a Bias

  7. In the end • Media bias Tin Can 11 - A Bias is a Bias is a Bias

More Related