What do you mean by quality control innovations?

Most likely things like version control, static analysis, dynamic analysis (e.g. Valgrind), automated testing, and code review. The Joel Test[0] is a good starting place.

[0]http://www.joelonsoftware.com/articles/fog0000000043.html

Actually, Joel has a lot of great blogs, not just the one on the Joel test. Browse through the titles and read any that seem interesting. He has been writing good material for many years. Of course he is not the only great blogger on the topic of software engineering, so whenever you need to google for info on a topic, click on the More... dropdown and select Blogs to find more great bloggers.

I've read some of Joel's posts in the past and will definitely keep this in mind.

Quality control innovations: Requirements reviews, Test driven development, Agile. Have a read of Software Inspection by Tom Gilb. The exercises at the back of A Discipline for Software Engineering are also very good (although the main book is not that good).

Edit: It is worth understanding "bugs removed per hour". Every quality control "innovation", has a bug removal rate and will improve the end product, or should do. The bug removal rate, is a calculation you can do. ... But I like to learn by doing, so the above exercises helped me understand.