Evaluations Are Arguments
X is (is not) a good Y because it meets (or fails to
meet) criteria A, B, and C.
Computer-aided instruction (CAI) is an effective
teaching method because it encourages self-paced
learning.
Arguments make claims (CAI is an effective teaching
method) and offer reasons (because . . . ). Then,
they provide evidence to support their reasons
(examples of different learners).
The give rise to a warrant, which is the assumption
that joins the claim and stated reasons:  self-paced
learning is an effective teaching method.