text: But then I'm not sure we're measuring the same type of project included in the Eclipse database. Our projects are all - or at least predominently - standalone projects or releases as opposed to modules that will be assembled into a larger product. That may be one explanation for the differing behavior. Another may be that the MIT graph plotted % of Defects (in the program as a whole?) against % of Programs (the percent of the entire program's size represented by individual software modules?). That's a different metric.
  Still another possibility is that (as Tedesco observed earlier) the real driver behind defect density is not actually code size but connectivity. In an object oriented world, this makes a lot of sense: the more different modules make use of Module A, the higher the probability something in Module A will conflict with one of the many other modules it must exchange information and interact with. In many ways, the object model is an enormous complexity factor in and of itself.
  At any rate, it's an interesting question. I'd be interested to know if anyone has taken a look at the relationship between defect density and project size with their own data?