WIC version 16_1 Version History

TRIM3 WIC Module

TThe TRIM3 WIC module simulates the Special Supplemental Nutrition Program for Women, Infants and Children (WIC). The simulation corrects for under-reporting of program benefits in survey data and estimates the value of WIC food benefit packages to the simulated recipients for use in expanded definitions of family resources.

WIC is a federal grant program for which Congress annually authorizes a specific amount of funding; it is not an entitlement program. WIC is administered by the USDA’s Food and Nutrition Services agency and by state and local agencies. In addition to providing supplemental foods, the WIC program also provides nutrition education and promotes breastfeeding. TRIM3’s WIC module simulates only the receipt and value of supplemental foods.

TRIM3 simulates eligibility for the WIC program on a monthly basis, capturing the actual program rules as closely as possible (but with limited ability to identify women who are eligible due to pregnancy). The simulation of participation takes into account the program’s 6-month and 12-month certification periods. The value of the monthly benefit package varies by category of recipient--infants, young children, and women--and can also vary by state.

This documentation describes each of the modeling steps in detail, as follows.

• Eligibility
• Demographic Eligibility
• Income Eligibility
• Adjunctive Eligibility
• Participation
• Participation Decision in a Baseline Simulation
• Certification Periods
• Participation Decision in an Alternative Simulation
• Value of WIC Benefits and Other Rules
• Output Variables

ELIGIBILITY

TRIM3's WIC module checks for eligibility in each month of the simulation year. An individual might be found eligible for WIC in some months of the year but not the entire year. Under actual program rules, a person must be demographically eligible, either income eligible or adjunctively eligible, and nutritionally at risk. TRIM3 simulates demographic requirements and income or adjunctive eligibility requirements but assumes that all individuals who meet those tests are nutritionally at risk. (The procedures used by the Food and Nutrition Service (FNS) to estimate WIC eligibility assume that among otherwise-eligible individuals, almost all are at nutritional risk.)

Demographic Eligibility

To be eligible for WIC, an individual must be an infant (age 0), a young child, a post-partum woman (the mother of an infant), or a pregnant woman. The program rule MaxAgeofChild sets the maximum age at which a child is eligible for WIC (set to 4 to model actual program rules). Infants and young children are identified based on their age as of the survey. (For simplicity, a child age X as of the survey is treated as age X for the entire simulation year.) Post-partum women are identified as women who have an "own child" who is age 0.

The model has limited ability to identify pregnant woman because pregnancy is not reported in the surveys generally used as input to TRIM. However, if a woman of childbearing age (hardcoded at ages 14 to 44) reports receipt of WIC benefits in the survey, and there are no infants or young children (no older than one year older than MaxAgeOfChild) in the woman's household, the model considers her potentially eligible for WIC due to pregnancy in April through December of the simulation year. If the input data being used for a particular simulation do have an indicator for pregnancy, that variable can be specified in the input variable parameter PregnancyStatus. The program rule PregnancyOption indicates whether PregnancyStatus alone is used to indicate pregnancy, or if women of childbearing age who report WIC without having age-eligible infants/children should also be considered pregnant. Note that a woman is only treated as having reported WIC if the information was truly reported, not if the receipt was "allocated" (imputed) to fill in missing data. In alternative simulations, variable list program rule BaselineWICDemoElig enables analysts to keep eligibility due to pregnancy consistent with the baseline.

Income Eligibility

To be fully eligible for WIC based on income, a demographically-eligible individual must live in a family with income at or below an income threshold.

Program rule IncomeEligiblityTestType indicates the type of threshold. If that rule is set to base eligibility on the federal poverty guidelines (which is the default), the program rule PercentOfPoverty contains the multiple of poverty (set to 1.85 to model actual program rules) and the rules PovertyGuidelineUS, PovertyGuidelineHawaii, and PovertyGuidelineAlaska hold the poverty guidelines. To capture the fact that real-world program shifts from one set of poverty guidelines to another in the middle of the calendar year, the PovertyGuideline rules can be set to the average of the set of guidelines used in the first half of the year and the set of guidelines used in the second half of the year. Each Poverty Guideline program rule includes a base value (for family size of 1) and an amount to add for each additional person in the family. (The rules hold the annual guidelines, but the TRIM3 code converts to monthly amounts for comparison with monthly family income amounts.)

IncomeEligibilityTestType can also be set to use a different set of income limits, other than limits based on the official poverty guidelines. For example, this option could be chosen to use income limits that vary by geographic areas. If this option is chosen by the analyst, variables providing the income limits are specified in the input variable parameter IncomeLimitVars.

With either setting of IncomeEligiblityType, the specific income eligibility threshold varies by the size of the family. FamilyType is a national-level rule that defines the family unit for purposes of determining eligibility. There are three possible settings. One option is to treat the entire household as the family unit; in this case, an unrelated subfamily and any unrelated individuals are combined with the primary family and all considered as one unit. Another option combines related subfamilies with the primary family, but treats unrelated subfamilies and individuals as separate assistance units. The third possible approach is to treat both related and unrelated subfamilies as separate units. If FamilyType is set to either of the options other than considering the entire household as one unit, the program rule UnmarriedParentInUnit controls the treatment of households that include two parents who are unmarried. According to Census Bureau family coding, only one unmarried parent is in the same "family" as the children, because the other parent is considered "unrelated" to the first parent. The rule UnmarriedParentInUnit can be set to include both parents in the same unit as the children, even when other unrelated individuals are not being included.

An additional adjustment to family size is made for families that appear to include a pregnant woman. In those cases, the family size is increased by 1. (This rule is not parameterized.)

For each family with demographically-eligible people, family income is determined in each month of the year by adding the variables specified by the EarnedIncome and UnearnedIncome input variable specification parameters, over all family members. The IncomeType program rule can be set to count only earned income, or only unearned income (the default is to count both).

Adjunctive Eligibility

Under actual program rules, an individual who is demographically eligible but not in an income-eligible family may be eligible for WIC due to enrollment in certain other programs—a policy known as "adjunctive eligibility." The program rules IsFoodStampsElig, IsMedicaidElig, and IsTANFElig can be set to "Yes" to indicate that an individual is adjunctively eligible based on enrollment in SNAP (Food Stamps), Medicaid, or TANF. (Only individuals who are demographically eligible but not income-eligible are marked as adjunctively-eligible.)

If IsTANFElig is set to "yes," and the variable in MonthlyTANFReceipt is positive, indicating that an individual is a member of a TANF assistance unit with benefits in this month, then the person is adjunctively eligible. If IsFoodStampsElig is set to "yes", and MonthlyFoodStampsReceipt is greater than zero, indicating that the person is a member of an assistance unit receiving SNAP (food stamps), then the person is adjunctively eligible. If IsMedicaidElig is set to "yes," and MonthlyMedicaidReceipt indicates that the person is enrolled in Medicaid or a Medicaid expansion program, then the person is adjunctively eligible. Additionally, if a family includes a pregnant woman or infant who is enrolled in Medicaid or a Medicaid expansion program, all demographically-eligible family members are adjunctively-eligible for WIC (if not already income-eligible).

PARTICIPATION

TRIM3 simulates WIC enrollment on a family basis. Families may be simulated to enroll for all, some, or none of the months in which individuals are eligible. However, the simulation takes into account the fact that certification periods vary by type of individual. In an alternative (non-baseline) simulation, participation may depend in part on the participation decision in the baseline simulation.

Participation Decision in a Baseline Simulation

When parameter SimulationMode is set to "baseline simulation", the participation status of eligible families is determined based on the family's characteristics, their survey-reported WIC enrollment status (if available in the data), and the parameterized participation probabilities and adjustments. For all families with at least one person who is fully-eligible for WIC (both demographically eligible and either income-eligible or adjunctively-eligible) in at least one month of the year, TRIM3 determines a yes/no participation status for that family as follows:

• If anyone in the family unit reports WIC (a true report, not counting allocated reports) then every fully-eligible person in the unit will participate in part or all of the year.
• If no individual in the family reports WIC, the family's probability of WIC participation is compared to the family's random number for purposes of WIC participation. If the random number is less than the probability, the eligible family members will each be simulated to enroll for at least part of the year.
• The family's probability is initially obtained from the program rule ParticipationProbability, which includes state-specific probabilities for three types of families: (1) families that include an eligible infant, (2) families that do not include an eligible infant, but that include an eligible child, and (3) families that do not include an eligible infant or child. The third group occurs only to the extent that women have been identified in the simulation as eligible due to pregnancy (as discussed earlier in this documentation).
• Starting with release 13_4, participation probabilities may also vary by the race/ethnicity and by the age of the youngest WIC-eligible person in the family using program rules PartAdjRaceEth1 - PartAdjRaceEth5 and PartAdjAgeYoung1 - PartAdjAgeYoung7.

Certification Periods

For families selected to enroll, the number of months of enrollment for each person reflects the fact that individuals are "certified" to receive WIC benefits for either a 6-month or 12-month period. An individual must pass either the income or adjunctive-eligibility test in the first month of enrollment. However, in subsequent months, even if the person's family income increases above the income limit or the person stops receiving other benefits, such that the person is no longer income or adjunctively eligible, the individual still remains enrolled in WIC for the remainder of the certification period. Certification periods may vary by type of individual and by state. Certification periods are coded in parameter CertificationPeriod, which has three values for each state: for postpartum women, infants, and young children. (The certification period for a pregnant woman is assumed to be the duration of pregnancy and is not parameterized.)

To approximate the operation of certification periods, the module assigns enrollment as follows:

• An infant participates for periods equal to the state-specific value for infants in the CertificationPeriod parameter. A period starts with a month of full eligibility. If the period ends before the end of the year, the family must be fully eligible (based on income or adjunctive eligibility) in the subsequent month in order for the infant to continue participating.
• A young child participates for periods equal to the state-specific value for children in the CertificationPeriod parameter. A period starts with a month of full eligibility. If the period ends before the end of the year, the family must be fully eligible (based on income or adjunctive eligibility) in the subsequent month in order for the child to continue participating.
• A woman who is eligible based on having an infant may initially participate for a period equal to the state-specific number of months for women in the CertificationPeriod parameter. Half of the eligible women with an infant are selected to also be potentially eligible for an additional spell (of the same number of months as the applicable value of CertificationPeriod) based on an assumption that they are still breastfeeding. For that half of the mothers of infants, if they are income-eligible or adjunctively eligible in the month following the end of the first certification period, a second certification period is modeled. For the other half of mothers of infants, there is no eligibility following the first period, even if their family continues to be income-eligible or adjunctively eligible.
• A woman eligible based on pregnancy participates from the first month of full eligibility (during her assumed April-December pregnancy) to the end of the calendar year.

Unlike the modeling of eligibility and the annual participation decision, the modeling of certification periods is on a person-by-person basis rather than on a family basis. As a result, depending on the settings of the CertificationPeriod parameter and months in which the family is income-eligible or adjunctively eligible, some family members may receive WIC for more months than others.

Participation Decision in an Alternative Simulation

When parameter SimulationMode is set to "alternative simulation," the participation status of eligible families may take into account whether or not the family participated in a previous simulation, depending on the setting of the rule ParticipationInAlternativeSim. Specifically, the analyst may specify that all families that participated in the prior simulation will continue to participate if still eligible, or the analyst may specify that all families that were eligible in the prior simulation will make the same participation decision as made previously (either participating or not participating). The analyst may also choose to not model any additional participation beyond the families that participated in the prior simulation. If the analyst chooses any of these options, the input variable parameters BaselineWICEligibility and BaselineWICParticipation must hold the variables indicating eligibility and participation status in the prior simulation.

VALUE OF WIC BENEFIT AND OTHER RULES

The module assigns the value of WIC enrollment for each simulated recipient in each month of enrollment. Because states are given some flexibility in WIC food benefits, and due to the geographical variability of food costs, the value of a WIC benefit package may vary from state to state. The program rule StateValueOfWIC provides the average monthly value of a WIC food package benefit for each type of recipient (infants, young children, and women) for each state. For infants, the rule is generally set to the pre-rebate value of the benefit, which approximates what the family would have to pay to purchase baby formula without WIC (rather than the much lower post-rebate value, which is the cost of the benefit to the government).

StateToProcess indicates whether the module should operate on the entire input data file or only on households in one or more selected states.

OUTPUT VARIABLES

The module can produce numerous micro-level output variables. Key annual-level output variables are:

• AnnualUnitType--the type of individual or individuals eligible for WIC in a particular family--infant only, child only, woman only, woman and infant, woman and child, infant and child, or woman, infant and child.
• NumberFamilyPersons--This variable stores the family size used in calculating the income eligibility threshold. It also adds one if there is a woman who appears pregnant in the family.
• AnnualIncome--the family’s income for the year.
• AnnualWICEligibility--tells whether an individual has any WIC eligibility during the year and if so, if the person is income-eligible or adjunctively eligible.
• AnnualWICParticipation--if a person received WIC benefits in one or more months of the year.
• AnnualWICBenefitRcvd--the annual value of WIC benefits a participant is simulated to receive

Key monthly-level output variables include:

• MonthlyDemogEligType--tells whether a person is eligible or ineligible for WIC in each month; if they are eligible, the variable tells if the person is an infant, young child, postpartum mother, or pregnant woman.
• MonthlyWICEligibility--tells whether an individual is ineligible, income-eligible, or adjunctively-eligible in each month; note that an individual may be simulated as enrolled in some months when s/he is not simulated as eligible, due to the 6-month and 12-month certification periods.
• MonthlyWICParticipation--if a person received WIC benefits during a given month, or not.
• MonthlyWICBenefitRcvd--the monthly value of WIC benefits a participant is simulated to receive
• ValueOfWIC--a monthly-level variable storing the potential value of the WIC benefit package, for all persons/months eligible for WIC.