Which study analyzed questionnaires taken by followers as they described their leader behaviors?

I believe the answer is: Ohio state studies

The purpose of the studies were to find out what traits that a person need to become an effective leader. From the studies, they found that most leaders at lest possess these two traits as the bare minimum:

- People-oriented, which make them able to organize people to work together under a same goal

- Task oriented , they separate time to fragments that is dedicated solely to finish the taks that they need to finsih.