It doesn't seem that one's filing status should be confusing. You're single or you're married. But, many people qualify for head-of-household status. That one is confusing because of its multi-faceted definition.
The IRS offers an online questionnaire to help people figure out if they qualify for head-of-household status. For many years, the California Franchise Tax Board mailed questionnaires to individuals who claimed this status to let them know their status would be reviewed and provided information to help them confirm if they selected the proper status (click here for a sample letter). Starting in 2015, the FTB created a new form that must be completed and attached to the California income tax return if the head-of-household status is claimed (Form 3532).