margin of error vs safety margin

margin of error and safety margin both are nouns.

Word	Noun	Adjective	Verb	Adverb
margin of error	Yes	No	No	No
safety margin	Yes	No	No	No

As nouns, margin of error and safety margin are synonyms defined as:

margin of error and safety margin: the margin required in order to insure safety

Other synonyms of margin of error include margin of safety.

margin of error (noun)	safety margin (noun)
the margin required in order to insure safety	the margin required in order to insure safety