Estimating the Development Cost of Open Source Software
Report: Estimating the Development Cost of Open Source Software. Black Duck Software, 2009
"Black Duck Software (news, site) recently released a report stating that, by their calculations, the development cost of open source software is US$ 387 Billion. That's roughly half of the US stimulus bill.
Contributing to this value are over 200,000 open source projects with over 4.9 billion lines of code. Not only is all of this work worth a staggering amount in terms of dollars, it's also worth around two million developer years.
That's a lot of code. That's a lot of code that, since it's open source, you can incorporate into your own projects. In fact, Black Duck estimates that 10% of IT application development spending goes toward duplicating open source efforts.
Companies who instead turn to the open source code base could save US$ 22 Billion a year." (http://www.cmswire.com/cms/web-cms/open-source-code-worth-us-387-billion-004436.php)