[toolslive]

""" it's likely that adapting old code to a new context is less work than starting from square one again. """

It has been measured that changing more than 25% of software incurs more than 100% of the cost. So your mileage may vary.

[jasonwatkinspdx]

I think it depends where you draw the line. These comparisons can be hard to make due to different accounting of what counts as "reuse." In this reply to a friend I was taking a very broad economic like view. For example: no one is rewriting the linux kernel from the ground up to launch an ecommerce app. Likewise people generally aren't rewriting the functionality provided by their langauges' standard libraries for each app. So in the broadest sense of all labor involved, there's a lot more reuse going on than a more narrow experiment may consider.

[SkyMarshal]

Any chance you remember where that measurement came from? I could use that with a client right now, given we're discussing a major refactor of about 25%-30% of the code base.

[toolslive]

It was mentioned in this talk: http://vimeo.com/9270320 and in the corresponding book "making software" http://shop.oreilly.com/product/9780596808303.do

have fun.

[asabjorn]

Have you been able to find the Thomas et al paper that supports this claim? I have been unable to find it, and others seem to have this problem as well:

http://www.gdb.me/computing/citations-greg-wilson-cusec.html

[toolslive]

the slides from the talk are here: http://www.slideshare.net/gvwilson/bits-of-evidence-2338367 (see slide 20)

I realized today I got it from somewhere else.. (Facts and fallacies of Software engineering) Looking up the whole reference in that book gave me the title, and googling that gave me the the paper

http://drum.lib.umd.edu/bitstream/1903/703/2/CS-TR-3424.pdf