Final answer:
The confusion surrounding performance measures and design cases arises from challenges in defining and describing performance measures, the impact of poor design decisions, and the questioning of the relationship between financial resources and student performance.
Step-by-step explanation:
The confusion regarding the way performance measures relate to design cases arises from several challenges and controversies. One key aspect is the difficulty in defining and describing performance measures consistently, leading to inconsistencies and questioning of study results. Another aspect is the impact of poor design decisions on the ability to develop a successful design that meets customers' needs. Additionally, the allocation of increased financial resources in education has led experts to question whether the problems lie in the structure rather than the resources spent.