The most common and most likely answer to this crossword clue is the 4 plus 4 plus 5 letter word BODY MASS INDEX
B
O
D
Y
M
A
S
S
I
N
D
E
X
Buddy explains!
The straight part
We know that "criterion for rating figures" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case criterion for rating figures = body mass index.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.