Non-functional requirements are the criteria that define the quality, performance, security, usability, and other aspects of a product1. They are often implicit or assumed, but they are important to make visible and explicit, as they affect the value and satisfaction of the product2. One effective way to make non-functional requirements visible is to add them to the Product Backlog, which is an ordered list of everything that is known to be needed in the product[3][3]. By adding non-functional requirements to the Product Backlog, the Product Owner and the Developers can prioritize, refine, and estimate them, and make them transparent to the stakeholders4. Another effective way to make non-functional requirements visible is to add them to the Definition of Done, which is a shared understanding of what it means for work to be complete, and ensures transparency of the quality of the work done5. By adding non-functional requirements to the Definition of Done, the Developers can ensure that every Product Backlog item and Increment meets the expected quality standards, and that the work is taken care of every Sprint.

References:

1: Non-functional requirement, Wikipedia, accessed on December 16, 2023

2: Managing Products with Agility, Scrum.org, accessed on December 16, 2023

[3][3]: The Scrum Guide, November 2020, p. 6

4: The Scrum Guide, November 2020, p. 7

5: The Scrum Guide, November 2020, p. 13

 Understanding and Applying the Scrum Framework, Scrum.org, accessed on December 16, 2023