I read some years ago about cyclomatic complexity and things like that and i was wondering if there were other measures not oriented to the code itself but to the design in general. I mean, it is considered that a module or function is complex enough to break into smaller and separated ones when it has more than X lines of code (relatively speaking) Is there such studies applied to OOP design in general? like how many attributes on a class are considered too many, how many methods rates the class as ''complex'', how many classes are considered too many for a given subject?