This is the 1445th most frequent Korean word.
조사한
"조사한" means "investigated" or "examined."
In this sentence, '조사한' functions as an adjective-like modifier, describing '결과' (results) as those that were researched.
그는 하루 종일 조사한 결과를 발표했다.
He presented the results he had researched all day.
Here, '조사한' is used with '후에' to indicate an action completed prior to making the decision.
조사한 후에 결정을 내리는 것이 중요하다.
It is important to make a decision after researching.
In this usage, '조사한' describes '자료' (materials), indicating they were researched.