The Product might be an event, a piece of art, a website, a performance, a model, etc. Whatever the outcome, the student will reflect on and judge the success of their Product as part of their process. How well their Product turns out is less important than how they plan for and learn from creating it. The student should have an idea of what a excellent Product looks like, so they know what to aim for as they are designing it. This is where success criteria come in.
(These are also called "Product Specifications")
Criterion Aiii: present a clear, detailed plan for achieving the product and its associated success criteria.
Criterion Cii: evaluate the product based on the success criteria.
There are a few ways you can structure your specifications and areas with which you can chose to score your product.
This worksheet for writing your rubric includes samples.
Portions of this presentation were taken from ISS & Lenny Dutton's personal project page