A week after I introduce the new high-frequency words to the class, I will individually assess each student to see if they have learned the words.
On the teacher data sheet I'll place a check under the asterisk if they know the word or under the "not yet" if they need more practice. I make sure they can tell me the word on two different days (hence the two areas under asterisks) before I stop assessing each word during the individual assessments.
I like having as few papers as possible so I've designed this data sheet to be printed back to back on one paper. A whole year's worth of assessment on one sheet!