The other three were "optional referendums", which meant that only a majority of the public vote was required for the proposals to be approved.

The referendum on the criminal law was an "optional referendum", which required only a majority of the public vote.

This was the first "optional referendum" held in the country, as all previous referendums had been "obligatory referendums".

The referendums were "optional referendums", which required only a majority of the public vote, rather than a majority of votes and cantons.

On the same day voters approved two other major political reforms, Proposition 4, which granted women the vote, and Proposition 7, which introduced the initiative and the optional referendum.

Proposition 7 of 1911 (or Senate Constitutional Amendment No. 22)) was an amendment of the Constitution of California that introduced, for the first time, the initiative and the optional referendum.

On the same day as Proposition 4, voters enacted the modern system of direct democracy in California, by approving Proposition 7, which introduced the initiative and the optional referendum, and Proposition 8, which introduced the recall of public officials.

In California a vote on a measure referred to voters by the legislature is a mandatory referendum; a vote to veto a law that has already been adopted by the legislature is an optional referendum or "people's veto"; the process of proposing laws by petition is the initiative.