Final answer:
The agile project management principle that involves testing assumptions early, building prototypes, and refining product requirements through customer feedback is Experimentation and adaptation,
Step-by-step explanation:
The principle of agile project management that is described by testing assumptions early and building working prototypes to solicit customer feedback and refine product requirements is Experimentation and adaptation. This involves an iterative process of developing a prototype, testing it, and using the test results to refine the product.
Through iterative testing and evaluation, prototypes are assessed against certain criteria and constraints. The spiral design process mentioned outlines the necessity to go back and revisit stages as new information and feedback are gathered, ensuring that the product will meet its intended purpose efficiently.
Using this practice, agile teams are able to continuously improve the product by adapting their design based on real-world feedback. This process not only validates the design but also enhances its development, reflecting a commitment to creating the highest value for customers while addressing any issues as early as possible in the development cycle.