The process in which policy is created through the combined efforts of interest groups, a state agenc, and a legislative committee is called

It's called  the "iron triangle" .

Explanation:

The "iron triangle" is a term used by political scientists to classify the policy-making association with the three groups cited on the question (interest groups, congressional committees and the bureaucracy). The main objective is to create and consolidate their own power base, making allies and have more influence through the political arena.

answer; severe;