There are four types in Michigan, (1) statutory initiative, (2) voter referendum, (3) legislative referendum, and (4) constitutional amendment initiative. Ours is the first type, a statutory initiative. For a more detailed explanation of the types of initiative and referendum, go here and scroll to the bottom: http://www.crcmich.org/election/index.html. For a history of initiative and referendum in Michigan, see question and answer below.