all-encompassing vs across-the-board

all-encompassing and across-the-board both are adjectives.

Word	Noun	Adjective	Verb	Adverb
all-encompassing	No	Yes	No	No
across-the-board	No	Yes	No	No

As adjectives, all-encompassing and across-the-board are synonyms defined as:

Other synonyms of all-encompassing include all-embracing, all-inclusive, blanket, broad, encompassing, extensive, panoptic, wide.

all-encompassing (adjective)	across-the-board (adjective)
broad in scope or content	broad in scope or content