Common QC tests include relationship (child, stepchild, foster child placed by an authorized agency or court, sibling, or qualifying descendant), age (generally under 19, or under 24 and a full-time student, and younger than 1 the taxpayer; or permanently and totally disabled at any age), residency (generally lived with taxpayer more than half the year, subject to exceptions), support (child did not provide more than half of their own support), and joint return (generally no joint return except solely to claim a refund of withholding or estimated tax). A child must also satisfy applicable citizenship/residency requirements for dependency purposes. Tie-breaker rules may apply when
multiple taxpayers could claim the same child.