* A referendum is a decision by the legislature that is put to the electorate to approve or reject. This is done in response to a citizen petition, a decision by the state legislature or a state constitutional requirement.
* A constitutional amendment is placed on the ballot by the legislature or by the electorate through a petition drive.
Each state has its own quirky and tricky laws regarding ballot proposals: In Arizona, for example, each petition can only have 15 signatures per page or all names are declared null. Some states require signatures from a percentage of voters in every region, sending signature gatherers into rural areas. Others, like Colorado, just need a percentage of the voters in the last gubernatorial race, freeing up signature gatherers to concentrate on the more populated urban areas.
This November, voters around the country will vote on 93 statewide ballot measures, after 488 petition attempts. This is up from 1994, when 509 petition attempts yielded only 76 ballot measures for public votes. Only 25 passed. Initiatives and referenda have always been difficult processes to put into practice. In 1898, South Dakota became the first state to allow what has been called "direct democracy," but ballot measures weren't used until 1904, when Oregonians voted on an initiative to allow counties to ban the sale of liquor.
Understanding a ballot question is often an exercise in interpreting jargon. Ballot measures are notorious for being confusing, wordy and vague, sometimes even leading people to vote "yes' when they mean "no."