What is the purpose of a referendum?

The purpose of a referendum is to allow voters to directly decide on specific legislative measures or changes to state law. This process empowers citizens to have a direct say in governance, particularly on significant issues that may affect the public, thus enhancing democratic participation. In essence, a referendum serves as a tool for the electorate to approve or reject proposed laws or constitutional amendments, making it a vital mechanism for direct democracy.

In contrast, the other options, while related to public policy and government functions, do not accurately reflect the primary intent of a referendum. Gathering public opinion tends to be more about assessing general sentiments rather than making binding decisions. Creating a new agency involves administrative actions taken by the government rather than direct voter input. Amending the state constitution may sometimes involve referendums, but it is not the sole purpose of such a process; thus, it's broader than just amendments. Therefore, the essence of a referendum is captured well by stating that its primary function is to enable voters to directly influence state legislation.