The top bug predictor is not technical, it's organizational complexity
This is a no-brainer.As a development manager for a quarter-century, and an active software developer for a lot longer than that, I can definitely say that every place there's a "meeting of the minds" is a place for bugs.In the software itself, the more complex the design, the more of these "trouble nodes" (what I call them) there are. Each interface, each class, each data interface, is a bug farm.That's why I'm a skeptic of a number of modern development practices that deliberately increase the complexity of software. I won't name them, because I will then get a bunch of pithy responses.These practices are often a response to the need to do Big Stuff.In order to do Big Stuff, you need a Big Team.In order to work with a Big Team, you need a Big Plan.That Big Plan needs to have delegation to all the team members; usually by giving each one a specific domain, and specifying how they will interact with each other in a Big Integration Plan.Problem is, you need this "Big" stuff. It's crazy to do without it.The way that I have found works for me, is to have an aggregate of much more sequestered small parts, each treated as a separate full product. It's a lot more work, and takes a lot more time, with a lot more overhead, but it results in a really high-quality product, and also has a great deal of resiliency and flexibility.There is no magic bullet.Software development is hard.