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Thanks Janet. I actually want to know the hand-calculations as well (an old school thing)! Thanks Pablo. I’m familiar with DECIDE and iSOF but great to share here as well. Best From: "Evidence based health (EBH)" <[log in to unmask]<mailto:[log in to unmask]>> on behalf of Pablo Alonso Coello <[log in to unmask]<mailto:[log in to unmask]>> Reply-To: Pablo Alonso Coello <[log in to unmask]<mailto:[log in to unmask]>> Date: Tuesday, 16 February 2016 09:37 To: "[log in to unmask]<mailto:[log in to unmask]>" <[log in to unmask]<mailto:[log in to unmask]>> Subject: Re: RD/ARR & NNT from pooled RR/OR Dear all, Forgot to mention that the tools developed by GRADE are able to do all this as well as including friendly interactive presentations. All this was possible partly by an EU funded project called DECIDE (http://www.decide-collaboration.eu/) iSoF http://isof.epistemonikos.org/#/ Explore an example here: http://isof.epistemonikos.org/#/finding/55ddb808352a506111abe4ea Go to the table and activate the visual overview. GRADE decided not to include NNTs due to their shortcomings though! Guideline Development Tool (includes the iSoF for diagnostic/screening questions and will include the general iSoF in the future) http://gradepro.org/ Pablo PS. A nice video about DECIDE is available at https://www.youtube.com/watch?v=w30RunwobFI#action=share https://youtu.be/w30RunwobFI ________________________________ De: Janet Martin [[log in to unmask]<mailto:[log in to unmask]>] Enviat el: dimarts, 16 / febrer / 2016 00:08 Per a: [log in to unmask]<mailto:[log in to unmask]>; Pablo Alonso Coello Tema: Re: RD/ARR & NNT from pooled RR/OR Hi from Canada, An extremely useful tool for calculating ARR and NNT from a pooled RR/OR is available for free online (VisualRx, by Chris Cates), at http://www.nntonline.net/visualrx/ The tool obviates the need for hand-calculations, rightly pointed out by Andrew. Plus, the tool allows you to display the results as an icon array. I have found this tool very helpful, for my students, as well as for my colleagues, and even for patients. It also works quite well for convincing policy-makers about the worthiness (or lack thereof) of a new versus established interventions. Cheers, Janet ______________________________________________ Janet Martin, PharmD, MSc(HTA&M) Director, Medical Evidence, Decision Integrity & Clinical Impact (MEDICI) Assistant Professor, Department of Anesthesia & Perioperative Medicine and Department of Epidemiology & Biostatistics Schulich School of Medicine & Dentistry, Western University Room B3-412, 339 Windermere Road London, ON Canada N6A 5A5 Tel: 1-519-685-8500 x34482 Email: [log in to unmask]<mailto:[log in to unmask]> >>> Pablo Alonso Coello <[log in to unmask]<mailto:[log in to unmask]>> 2016/02/11 6:58 AM >>> This might be helpful http://www.jclinepi.com/article/S0895-4356(12)00032-7/abstract (section 8) Also this one we published recently might be of interest http://www.ncbi.nlm.nih.gov/pubmed/26560992 Pablo Pablo Alonso Coello Centro Cochrane Iberoamericano Instituto de Investigación Biomédica (IIB Sant Pau) CIBER Epidemiología y Salud Pública (CIBERESP) C/ Sant Antoni Maria Claret 167 (Pabellón 18, planta cero) 08025 Barcelona | España [log in to unmask]<mailto:[log in to unmask]> | Skype: tartanedo T: (+34) 93 553 78 14 | F: (+34) 93 553 78 09<tel:%28%2B34%29%2093%20553%2078%2009> ________________________________ De: Evidence based health (EBH) [[log in to unmask]<mailto:[log in to unmask]>] en nom de David Nunan [[log in to unmask]<mailto:[log in to unmask]>] Enviat el: dijous, 11 / febrer / 2016 12:22 Per a: [log in to unmask]<mailto:[log in to unmask]> Tema: RD/ARR & NNT from pooled RR/OR Hi All, Can anyone advise on calculating risk difference/absolute risk(odds) reduction (and subsequent NNT) from pooled RR/OR. I’ve seen some calculate this based on the control event rate as a product of the weighted pooled effect estimate but can’t find any lit to support this. A worked example to illustrate: Treatment event rate: 32/1424 = 0.022 Control event rate: 71/1546 = 0.046 Pooled OR: 0.45 RD/ARR: 0.046*0.45 = 0.021 (or 2.1%) Is this right or wrong or somewhere horribly fuzzy in between? Best, David ________________________________ This information is directed in confidence solely to the person named above and may contain confidential and/or privileged material. This information may not otherwise be distributed, copied or disclosed. If you have received this e-mail in error, please notify the sender immediately via a return e-mail and destroy original message. Thank you for your cooperation.