The most common and most likely answer to this crossword clue is the 8 letter word INFERRED
I've seen this crossword clue in The Daily Telegraph
I
N
F
E
R
R
E
D
Buddy explains!

The straight part
We know that "Concluded" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case concluded = inferred.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.
What does INFERRED mean?
INFERRED verb- To introduce (something) as a reasoned conclusion; to conclude by reasoning or deduction, as from premises or evidence.
- To lead to (something) as a consequence; to imply. (Now often considered incorrect, especially with a person as subject.)
- To cause, inflict (something) upon or to someone.
- To introduce (a subject) in speaking, writing etc.; to bring in.