Enter on line 2b the combined modified AGI for your dependents
who are required to file an income tax return because their
income meets the income tax return filing threshold. Use
Worksheet 1-2 to figure these dependents’ combined modified
AGI. Do not include the modified AGI of dependents who are
filing a tax return only to claim a refund of tax withheld or
estimated tax.
Form 8814. If you are filing Form 8814, Parents' Election To
Report Child's Interest and Dividends, and the amount on Form
8814, line 4, is more than $1,100, you must include on line 1 of
Worksheet 1-2 the sum of the tax-exempt interest from Form
8814, line 1b; the lesser of Form 8814, line 4 or line 5; and any
nontaxable social security benefits your child received.
https://www.irs.gov/pub/irs-pdf/i8962.pdf