ongoing evaluation vs rating

ongoing evaluation and rating both are nouns.

Word	Noun	Adjective	Verb	Adverb
ongoing evaluation	Yes	No	No	No
rating	Yes	No	No	No

As nouns, rating is a hypernym of ongoing evaluation; that is, rating is a word with a broader meaning than ongoing evaluation:

ongoing evaluation: An evaluation undertaken during the implementation phase of a project.
rating: an appraisal of the value of something

Other hypernyms of ongoing evaluation include evaluation, valuation.

ongoing evaluation (noun)	rating (noun)
An evaluation undertaken during the implementation phase of a project.	act of ascertaining or fixing the value or worth of
	an appraisal of the value of something
	standing or position on a scale
	rank in a military organization