Child support & custody methodology

Model 1: Income Shares (38 states + DC)

Income Shares mechanic:

1. Combined Adjusted Gross Income (CAGI):
     CAGI = obligor income + custodial parent income

2. Basic Child Support Obligation (BCSO):
     Lookup from state's guideline schedule by CAGI + # children
     (Each state publishes its own table.)

3. Obligor's proportional share:
     Obligor's share % = obligor income / CAGI
     Obligor's BCSO = BCSO × obligor's share %

4. Add-ons (apportioned by income share):
     + Health insurance premium for child(ren)
     + Work-related childcare costs
     + Extraordinary medical expenses

5. Shared custody adjustment (if overnights > threshold):
     State-specific reduction formula

= Monthly child support obligation

Policy theory: children should receive the proportion of parental income they would have received if the family had remained intact. Both parents' incomes are part of the calculation; the obligor (non-custodial) pays their pro-rata share. Adopted by 38 states + DC. Source documentation: each state's child-support guideline statute (varies by state — e.g., Cal. Fam. Code §4055, NY DRL §240(1-b), Tex. Fam. Code §154).

Model 2: Percentage of Obligor Income (6 states)

Percentage of Obligor Income mechanic:

Monthly child support =
    Obligor's adjusted gross income × statutory percentage

Statutory percentage scales by # children:
    1 child:   typically 17–20%
    2 children: 25–28%
    3 children: 29–33%
    4 children: 31–35%
    5+ children: state-specific

Custodial parent's income: irrelevant to base calculation
(may affect deviation analysis)

Used by Alaska, Arkansas, Mississippi, Nevada, North Dakota, Wisconsin. Texas uses a Percentage of Obligor Income variant with statutory caps. Simplest math, fewest disputes, but criticized for ignoring the custodial parent's income — a wealthy custodial parent receives the same support from a low-income obligor as a low-income custodial parent would. Add-ons (childcare, health insurance) are typically additional to the percentage; not apportioned by income share.

Model 3: Melson Formula (3 states)

Melson Formula mechanic (Delaware, Hawaii, Montana):

Step 1: Self-Support Reserve (SSR)
    Both parents retain a Self-Support Reserve
    (minimum living standard threshold)
    SSR ≈ federal poverty level (varies by state)

Step 2: Primary Support Need (PSN)
    Determine minimum support need per child
    (state schedule, typically $300–500/child/month)

Step 3: Standard of Living Allowance (SOLA)
    After PSN is met, additional discretionary
    support based on remaining household income

Combined: Income Shares-style allocation +
         poverty-floor protection +
         SOLA top-up for higher incomes

Most complex of the three models. Reserves a basic self-support amount for the obligor before computing support; then layers in a SOLA component that gives the child a share of the family's higher standard of living. Used by Delaware, Hawaii, Montana. Considered most progressive across income ranges; produces lower obligations than Income Shares at low incomes (because of SSR floor) and higher at high incomes (because of SOLA).

Shared physical custody adjustment

Most state guidelines reduce support when overnights with the non-custodial parent exceed a threshold (typically 92, 110, or 128 nights per year). Formulas vary:

• Sliding-scale reduction: linear or stepped percentage reduction as overnights increase (Colorado, Indiana, Pennsylvania, others)
• Cross-credit method: each parent computes the support amount they would owe if the OTHER parent had primary custody; the higher-income parent pays the difference (Washington, Arizona, some others)
• Equal-shared-time orders: some states require equal-shared-time orders to fall outside the guideline entirely, with judicial discretion

Cross-state variance on this is large. The Bedrocka Tools calculator surfaces the state-specific threshold and adjustment formula at the result step. The methodology of shared-custody adjustment is one of the most-litigated parts of post-divorce child-support modifications.

Income definition + imputation

State statutes broadly include: W-2 wages, 1099 self-employment income, partnership distributions, bonuses, commissions, overtime, severance, pension distributions, Social Security disability (parent's benefit), workers' comp, unemployment, alimony received. Cross-state variance is largest on:

• Imputed income: if a parent is voluntarily unemployed or underemployed, some states aggressively impute earning potential based on prior earnings or BLS occupational wage data; others require proof of actual income
• In-kind benefits: housing provided by employer, company car, employer-paid travel — included in income in some states, not others
• Means-tested benefits: TANF, SNAP, SSI generally excluded from income for guideline purposes (federal regulation)
• Gifts and inheritances: typically excluded unless regularly recurring; case-specific

Update cadence + state-guideline review

Federal regulation 45 CFR §302.56requires states to review their child-support guidelines at least every 4 years. State Title IV-D agencies conduct economic studies to update guideline tables based on current cost-of-raising-children data + cost-of-living changes. Bedrocka Tools tracks these updates through state agency announcements and refreshes the calculator's guideline tables quarterly + on event-triggered basis.

Sources

• HHS Office of Child Support Services (OCSS) — federal oversight; cross-state guideline reference
• 45 CFR §302.56 — state guideline review requirement
• Each state's child-support guideline statute (e.g., Cal. Fam. Code §4055, NY DRL §240(1-b), Tex. Fam. Code §154, Fla. Stat. §61.30)
• State Title IV-D agency child-support worksheets (downloadable from each state child-support enforcement agency)
• Uniform Interstate Family Support Act (UIFSA) — interstate enforcement