Due diligence requires paid preparers to satisfy four tests when a return claims Earned Income Credit (EIC), Child Tax Credit (CTC), Additional Child Tax Credit (ACTC), Credit for Other Dependents (ODC), and head of household (HOH) filing status. What are the four tests? Complete Schedule 8812 (Form 1040), Credits for Qualifying Children and Other Dependents, submit all worksheets used to compute any of these four credits, ask questions, and take notes. Complete and submit Form 8867, Paid Preparer's Due Diligence Checklist, complete and keep all worksheets used to compute any of these four credits, satisfy the knowledge requirement, and satisfy the documentation requirement. Does this make sense, reasonable basis, substantial authority, nonfrivolous position. Knowledge, prepare, review, and file the tax return