What is the X in X-mas?
an evaluation and judgment of one's own abilities, actions, attitudes, etc.
1540s, "value of property for tax purposes," from assess + -ment. Meaning "determination or adjustment of tax rate" is from 1540s; general sense of "estimation" is recorded from 1620s. In education jargon from 1956.
The appraisal of property for the purposes of taxation.