okpolicy.org
Speaker McCall greenlights nearly 100 interim studies (Capitol Update) - Oklahoma Policy Institute
You can't read a lot into the 50 request denials. The Speaker doesn't have to give a reason, and his reason may be different for different requests and different members. It could be that he likes the idea but wants some other member to take the lead or he doesn't like the idea and doesn't want it to gain traction. In some instances, it may be about the author.