OneOrMultipleUnits specifies the method for dividing a household into SNAP units. If OneOrMultipleUnits is set to 0, then the entire household is treated as a single SNAP unit. The only members excluded from the unit are SSI recipients in cash-out states (who are excluded from the unit regardless of the value for OneOrMultipleUnits). The remaining options for OneOrMultipleUnits allow certain households to split into multiple units, subject to the constraint that married couples must file together and children must file with their parents. These options include:

1. A CPS household may be divided into one or more SNAP units, but children aged 18 or younger who are not married and do not have children of their own must file with their parents.
2. Any CPS household containing at least one TANF recipient may be divided into one or more SNAP units, but children aged 21 or younger (and their spouses and children) must file with their parents.
3. Any CPS household containing at least one TANF recipient may be divided into one or more SNAP units, but children aged 21 or younger who are not married and do not have children of their own must file with their parents.
4. Any CPS household containing at least one TANF recipient, or CPS household that reports unallocated receipt of SNAP benefits and reports that not everyone in the household receives SNAP benefits, may be divided into one or more SNAP units. Children aged 21 or younger (and their spouses and children) must file with their parents. "Other-relative" related subfamilies (i.e. neither head nor spouse is a child of the householder) must file with the householder if the head or spouse is under 18. Foster children who do not have a family of their own (i.e. they are unrelated individuals) must file with the householder.
5. A household may be divided into more than one unit, but children aged 21 or younger (and their spouses and children) must file with their parents. "Other-relative" related subfamilies (i.e. neither head nor spouse is a child of the householder) must file with the householder if the head or spouse is under 18. Foster children who do not have a family of their own (i.e. they are unrelated individuals) must file with the householder.
6. Any CPS household containing at least one TANF recipient, one SSI recipient, or CPS household that reports unallocated receipt of SNAP benefits and reports that not everyone in the household receives SNAP benefits, may be divided into one or more SNAP units. Children aged 21 or younger (and their spouses and children) must file with their parents. "Other-relative" related subfamilies (i.e. neither head nor spouse is a child of the householder) must file with the householder if the head or spouse is under 18. Foster children who do not have a family of their own (i.e. they are unrelated individuals) must file with the householder.
7. Any CPS household containing at least one TANF recipient, or CPS household that reports unallocated receipt of food stamps and reports that not everyone in the household receives food stamps, may be divided into one or more food stamp units (at the rate indicated by FamilySplitRate). Low-income non-TANF households that do not report SNAP, and non-TANF households where all persons are reported to receive SNAP, are split into multiple units based on the outcome of a logit model imputation. Children aged 21 or younger (and their spouses and children) must file with their parents. "Other-relative" related subfamilies (i.e. neither head nor spouse is a child of the householder) must file with the householder if the head or spouse is under 18. Foster children who do not have a family of their own (i.e. they are unrelated individuals) must file with the householder.
8. Households that receive TANF or have children less than 18 years of age may be divided into multiple units, but children aged 21 or younger (and their spouses and children) must file with their parents. "Other-relative" related subfamilies (i.e. neither head nor spouse is a child of the householder) must file with the householder if the head or spouse is under 18. Foster children who do not have a family of their own (i.e. they are unrelated individuals) must file with the householder.

TANF eligiblity is determined with references to program rules MonthlySimulatedAFDCPersonType and MonthlySimulatedAFDCBenefit. The FoodStamps module uses MonthlySimulatedAFDCPersonType to indicate each person's simulated categorical TANF eligibility status in order to determine if the household unit consists of a single family with no related subfamilies in which all persons are categorically eligible for TANF. MonthlySimulatedAFDCBenefit identifies persons simulated to receive TANF benefits.

Program rule UnrelatedPersonsUnitTreatment works in conjunction with OneOrMultipleUnits.

• If set to zero, there is no special treatment of unrelated subfamilies and individuals.
• If set to 1 and a household has not been split into multiple units under the methodology described above, then each unrelated subfamily and each unrelated individual are split into separate units. However, if an unrelated subfamily contains a member who is the unmarried partner of the household reference person, then that unrelated subfamily is combined with the unit of the household reference person. If an unrelated individual is the unmarried partner of the household reference person, that individual is included in the unit of the household reference person. Unrelated individuals under the age of 15 are also included in the unit if the household reference person.

If a household is to be split, a test is made as to whether it should just be split into broad units based on relationship (i.e. persons related to each other are treated as separate units, with unrelated individuals being treated as one-person units), or whether it can be further split by treating related subfamilies (and older children and relatives) as separate units. To be eligible for the subfamily-based split, a household must contain at least one family that meets the following criteria (for the purpose of these criteria, related subfamilies are considered as part of the primary family):

• At least one member must be a child or relative under 18 and not also a head or spouse of a related subfamily (Note: if OneOrMultipleUnits is set to 4, this criteria is ignored).
• At least one member must be a child or relative 18 or older and not also a head or spouse of a related subfamily OR the family must contain a related subfamily.

• OneOrMultipleUnits = 1 & 3: All related subfamilies become separate units.
• OneOrMultipleUnits = 2, 4, 5, 6, 7 & 8: All related subfamilies except those considered to be "young families" become separate units. A related subfamily is considered "young" if the head or spouse is a child of the householder and is 21 or younger (Note: if OneOrMultipleUnits is set to 4, a related subfamily where neither the head nor spouse is a child of the householder is considered "young" if either of them is under 18).

• 1: Over 18
• 2 & 3: Over 21
• 4, 5, 6, 7 & 8: Over 21, or over 17 if the person is not a child of the family

If OneOrMultipleUnits is set to 4, 5, 6, 7, or 8, foster children 15 or older are merged with the primary family's unit. For settings 1 through 3 of OneOrMultipleUnits, they file as one-person units. Foster children under the age of 15 always file as part of the primary family's unit.

Starting with version 50.0 and the 2007 ASEC, the person ids of biological, adoptive and step parents present in the household are available for every child. If the CPS variables BiologicalOrAdoptiveMotherID and BiologicalOrAdoptiveFatherID are specified in the FoodStamps module's variable list program rules BiologicalOrAdoptiveMotherID and BiologicalOrAdoptiveFatherID, the definition of the filing unit is further improved. Children that are unrelated to the householder with parents present in the household can be identified and put into the same filing unit as their parents.

After all other modifications to the filing units, if CohabitingParentTreatment is set to 1, all cohabiting biological or adoptive parents who are not the child's family or subfamily head will also be put in the same unit as the child. If the cohabiting parent has children in his or her own subfamily, then these kids are brought along into the same unit.