Like in coding, complexity in a business partnership might be a warning. The book Managing the Professional Service Firm by David Meister has a lot of lessons for anyone running a traditional parter/associates firm, and the last part talks about splitting the profits. My read is that a "dumb" approach (equal split or simple seniority-based) is okay, and a "judgment" approach (publish criteria, but have a committee make the final decisions) is okay, but a metrics-based approach is risky. I agree, and for small operations I think the simpler the better. Anyway, if it's something you're thinking about, the book is a solid, meaty read.