this system requires the assignment

this system requires the assignment of a rating evaluation for each selected performance category. Examples of ratings typically include: excellent, good, fair, and poor. These subjective evaluation can be completed by buyer, other internal users, or some combination of both.
The categorical approach is commonly used by smaller organizations because it is both easy and relatively inexpensive to implement. Although the categorical approach provides some structure to the measurement process, it does not provide sufficiently detailed insight into a supplier's true performance. Furthermore, because categorical systems often rely on manually collected data, an organization generates supplier performance reports less frequently than if an automated system existed. The reliability of the categorical method is the lowest of the three measurement systems discussed here, which limits the value of this approach when assessing supplier performance. There is often significant variance in the subjective ratings.