Complex sentence: The Waterfall model for software development is mistakenly attributed to Royce; in fact he demonstrated that while the development of large software systems required a more thorough approach, there was inherent risk in a single-pass sequential approach.
Split into simpler sentences: The Waterfall model for software development is mistakenly attributed to Royce. In fact Royce demonstrated that while the development of large software systems required a more thorough approach, there was inherent risk in a single-pass sequential approach.