From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Gauland Subject: Estimate ranges in column view Date: Thu, 17 Jun 2010 20:06:53 +0000 (UTC) Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: Received: from [140.186.70.92] (port=39468 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OPLPe-0006Up-CN for emacs-orgmode@gnu.org; Thu, 17 Jun 2010 16:10:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OPLPc-0006PF-5E for emacs-orgmode@gnu.org; Thu, 17 Jun 2010 16:10:10 -0400 Received: from lo.gmane.org ([80.91.229.12]:44587) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OPLPb-0006Ol-RQ for emacs-orgmode@gnu.org; Thu, 17 Jun 2010 16:10:08 -0400 Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1OPLPX-0004F3-KF for emacs-orgmode@gnu.org; Thu, 17 Jun 2010 22:10:04 +0200 Received: from 114-134-7-156.rurallink.co.nz ([114.134.7.156]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 17 Jun 2010 22:10:03 +0200 Received: from mikelygee by 114-134-7-156.rurallink.co.nz with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 17 Jun 2010 22:10:03 +0200 List-Id: "General discussions about Org-mode." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: emacs-orgmode-bounces+geo-emacs-orgmode=m.gmane.org@gnu.org Errors-To: emacs-orgmode-bounces+geo-emacs-orgmode=m.gmane.org@gnu.org To: emacs-orgmode@gnu.org When planning my work, I estimate the effort required as a range, rather than a single value. That is, instead of estimating a certain task will take 4 days, I'll use a range of 3-5 days. If I'm a bit less confident I know how long it will take, I'll use a wider range (e.g., 2-6 days). When I first started doing this, I switched from using a single 'Effort' column in org mode, to two columns (Effort_Low and Effort_High), simply summing each column to get an estimate for a composite task. However, this magnifies the level of uncertainty in the estimate. The final 'Effort_Low' value tells me what to expect if everything goes optimally; 'Effort_High' provides the extremely pessimistic view. More realistic summaries come from considering the range of each pair, using the combined statistical variance in each (low, high) pair to determine the variance in the final value. This is the method used by LiquidPlanner, for example. I've been mucking about with org-colview.el to automate this calculation for me, and am quite pleased with the results so far. I've approached this by adding a new summary type ("est") to org-columns-compile-map, and extending org-columns-number-to-string and org-columns-string-to-number to convert ranges to and from strings. This lets me populate an 'Estimates' column with values such as "[2 4]", and specify a summary type "est" to have the algorithm described above used to produce the final estimates. I have two questions for the list: 1. Is this the right approach, or should I change the behaviour of the existing EFFORT property? 2. Is this something others would find useful? Thanks, Mike