Is It Conflicting Information If Family Size Does Not Match the Tax Return?

No. According to SAI-Q8/A8 on the U.S. Department of Education's FAFSA Simplification Questions and Answers website:

"SAI-Q8: When an applicant self-reports a family size on their FAFSA form that is different from the family size received from the IRS, is this considered conflicting information that the school must resolve?

SAI-A8: No. The existence of both a family size field calculated from FTI and a self-reported family size field on the ISIR is not, by itself, considered conflicting information. In situations where family size from the IRS and family size self-reported by a contributor on the FAFSA form differ, the self-reported family size will be used for both the SAI and Pell Grant eligibility calculations. If a contributor does not self-report family size when presented with the option to do so, then the FTI family size will be used. It should be noted that, in any instance of an update or correction to ISIR data, no FTI field can be changed. Schools are directed to change income and tax fields using non-FTI data fields that will allow for manual entry that will essentially “override” FTI.

However, family size is still subject to verification. Therefore, if an applicant is selected for verification, the school must verify the family size used if the applicant self-reported it. In addition, if the school has reason to believe the self-reported family size is not correct, the school must treat this as conflicting information and take appropriate steps to resolve the issue."

FTI is federal tax information. ISIR is Institutional Student Information Record. SAI is student aid index.