by design vs by choice

by design and by choice both are adverbs.

Word	Noun	Adjective	Verb	Adverb
by design	No	No	No	Yes
by choice	No	No	No	Yes

As adverbs, by design and by choice are synonyms defined as:

Other synonyms of by design include advisedly, deliberately, designedly, intentionally, on purpose, purposely.

by design (adverb)	by choice (adverb)
with intention; in an intentional manner	with intention; in an intentional manner