Comments on: Why we can’t estimate software projects the same way we estimate houses http://www.summa-tech.com/blog/2009/01/28/why-we-cant-estimate-software-project-the-same-way-we-estimate-houses/ Summa Blog Wed, 08 Feb 2012 05:39:57 +0000 http://wordpress.org/?v=2.7 hourly 1 By: Users are from Venus, Developers are from Mars | Summa Blog http://www.summa-tech.com/blog/2009/01/28/why-we-cant-estimate-software-project-the-same-way-we-estimate-houses/comment-page-1/#comment-361 Users are from Venus, Developers are from Mars | Summa Blog Fri, 10 Apr 2009 15:00:58 +0000 http://www.summa-tech.com/blog/?p=88#comment-361 [...] approach is based on the flawed assumption that all development can be perfectly planned like building a house.  It assumes past projects failed (or ran over budget/schedule), because the users were not [...] [...] approach is based on the flawed assumption that all development can be perfectly planned like building a house.  It assumes past projects failed (or ran over budget/schedule), because the users were not [...]

]]> By: links for 2009-02-02 « pabloidz http://www.summa-tech.com/blog/2009/01/28/why-we-cant-estimate-software-project-the-same-way-we-estimate-houses/comment-page-1/#comment-47 links for 2009-02-02 « pabloidz Mon, 02 Feb 2009 12:02:11 +0000 http://www.summa-tech.com/blog/?p=88#comment-47 [...] Why we can’t estimate software projects the same way we estimate houses Summa Blog (tags: project) [...] [...] Why we can’t estimate software projects the same way we estimate houses Summa Blog (tags: project) [...]

]]> By: Jeff Howell http://www.summa-tech.com/blog/2009/01/28/why-we-cant-estimate-software-project-the-same-way-we-estimate-houses/comment-page-1/#comment-45 Jeff Howell Sat, 31 Jan 2009 16:40:03 +0000 http://www.summa-tech.com/blog/?p=88#comment-45 Another perspective is to think of the <i>creative</i> decisions necessary to build a house versus an application. Most of the creative decisions for the house are handled by the architect. The construction crew are not supposed to be creative, but rather to do what the architect has instructed. In software development, we still have the idea of an architect, and it is a creative function, but the developers also have a great number of decisions that are in the creative realm. These kind of decisions are much, much less frequent if you are a carpenter or a plumber. The point is that the creative process, choosing among many possibilities, has much higher variability and risk than executing a well known pattern. Another perspective is to think of the creative decisions necessary to build a house versus an application. Most of the creative decisions for the house are handled by the architect. The construction crew are not supposed to be creative, but rather to do what the architect has instructed.

In software development, we still have the idea of an architect, and it is a creative function, but the developers also have a great number of decisions that are in the creative realm. These kind of decisions are much, much less frequent if you are a carpenter or a plumber.

The point is that the creative process, choosing among many possibilities, has much higher variability and risk than executing a well known pattern.

]]> By: Frank Silbermann http://www.summa-tech.com/blog/2009/01/28/why-we-cant-estimate-software-project-the-same-way-we-estimate-houses/comment-page-1/#comment-43 Frank Silbermann Fri, 30 Jan 2009 13:42:21 +0000 http://www.summa-tech.com/blog/?p=88#comment-43 Actually, estimating the construction of a house only works well if performed by someone who has already built a number of houses with pretty much the same features and constructed out of the same materials. Likewise, if I've already built a dozen different programs all of which do pretty much the same thing and I'm going to build yet another by selecting from features existing in the first twelve, I can estimate that fairly well. The problem is that software developers are rarely contracted to build the same kind of program over and over again. The typical corporate developer does not build a set of slightly different accounting programs, one for each manager. Rather, each program he works on likely accomplishes a completely different task. Imagine if each construction firm built only one bridge, one road segment, one house, one skyscraper, one shopping mall, and one prison. Estimating would be a nightmare. Project failure would probably also be quite common. Actually, estimating the construction of a house only works well if performed by someone who has already built a number of houses with pretty much the same features and constructed out of the same materials. Likewise, if I’ve already built a dozen different programs all of which do pretty much the same thing and I’m going to build yet another by selecting from features existing in the first twelve, I can estimate that fairly well. The problem is that software developers are rarely contracted to build the same kind of program over and over again. The typical corporate developer does not build a set of slightly different accounting programs, one for each manager. Rather, each program he works on likely accomplishes a completely different task.

Imagine if each construction firm built only one bridge, one road segment, one house, one skyscraper, one shopping mall, and one prison. Estimating would be a nightmare. Project failure would probably also be quite common.

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