Locating and fixing bugs is the most expensive maintenance activity over the lifetime of the vast majority of software projects. Our recent research has shown that defective files seldom exist alone; they are architecturally connected, and they exhibit design flaws that are the root causes of their bugginess. Thus removing the architecture roots of bugginess is the key to reducing overall defect rates in a project. We prosecute this strategy by modeling architectures using a novel representation called design rule space (DRSpace)