What is the test for determining the intent of an initiative measure when the language in the ballot is ambiguous?

the statute as a whole and the overall statutory scheme [in light of the electorate's intent]. [Citation.] When the language is ambiguous, "we refer to other indicia of the voters' intent, particularly the analyses and arguments contained in the official ballot pamphlet." [Citation.]' [Citation.] In other words, 'our primary purpose is to ascertain and effectuate the intent of the voters who passed the initiative measure.'" (People v. Briceno (2004) 34 Cal.4th 451, 459.)