diff --git a/changelog.d/surviving-spouse-gross-income-test.fixed.md b/changelog.d/surviving-spouse-gross-income-test.fixed.md
new file mode 100644
index 00000000000..dee3be0c8fd
--- /dev/null
+++ b/changelog.d/surviving-spouse-gross-income-test.fixed.md
@@ -0,0 +1 @@
+Stop applying the qualifying relative gross income test to surviving spouse filing status, which IRC 2(a)(1)(B) disregards, and stop counting a dependent whose parent ids or relationship flags show they are not the filer's son, daughter or stepchild.
diff --git a/policyengine_us/tests/policy/baseline/household/demographic/tax_unit/filing_status.yaml b/policyengine_us/tests/policy/baseline/household/demographic/tax_unit/filing_status.yaml
index f993c6326da..2c3f50fec24 100644
--- a/policyengine_us/tests/policy/baseline/household/demographic/tax_unit/filing_status.yaml
+++ b/policyengine_us/tests/policy/baseline/household/demographic/tax_unit/filing_status.yaml
@@ -251,3 +251,112 @@
   output:
     # Each parent has 5,100 of taxable benefits, not below 4,400.
     filing_status: SINGLE
+
+- name: Widowed parent of a 29-year-old dependent with $6,238 of income files as surviving spouse.
+  period: 2025
+  input:
+    people:
+      head:
+        age: 67
+        is_surviving_spouse: true
+        is_tax_unit_head: true
+      adult_child:
+        age: 29
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        # IRC 2(a)(1)(B) disregards the IRC 152(d)(1)(B) gross income test,
+        # so income above the $5,200 limit does not matter.
+        employment_income: 6_238
+    tax_units:
+      tax_unit:
+        members: [head, adult_child]
+    households:
+      household:
+        members: [head, adult_child]
+  output:
+    filing_status: SURVIVING_SPOUSE
+    basic_standard_deduction: 31_500
+
+- name: Widowed filer with a dependent parent files as head of household, not surviving spouse.
+  period: 2025
+  input:
+    people:
+      head:
+        age: 67
+        is_surviving_spouse: true
+        is_tax_unit_head: true
+      parent:
+        age: 88
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        is_parent_of_filer_or_spouse: true
+    tax_units:
+      tax_unit:
+        members: [head, parent]
+    households:
+      household:
+        members: [head, parent]
+  output:
+    filing_status: HEAD_OF_HOUSEHOLD
+
+- name: Widowed grandparent of a dependent grandchild files as head of household, not surviving spouse.
+  period: 2025
+  input:
+    people:
+      head:
+        person_id: 1
+        age: 60
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      mother:
+        person_id: 2
+        parent_1_id: 1
+        age: 35
+        is_tax_unit_head: true
+        is_tax_unit_spouse: false
+      grandchild:
+        person_id: 3
+        parent_1_id: 2
+        age: 8
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+    tax_units:
+      head_unit:
+        members: [head, grandchild]
+      mother_unit:
+        members: [mother]
+    households:
+      household:
+        members: [head, mother, grandchild]
+  output:
+    filing_status: [HEAD_OF_HOUSEHOLD, SINGLE]
+
+- name: Widow whose own parent id is set still files as surviving spouse with a dependent child without ids.
+  period: 2025
+  input:
+    people:
+      head:
+        person_id: 1
+        parent_1_id: 90
+        age: 67
+        is_surviving_spouse: true
+        is_tax_unit_head: true
+      adult_child:
+        person_id: 2
+        age: 29
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        employment_income: 3_000
+    tax_units:
+      tax_unit:
+        members: [head, adult_child]
+    households:
+      household:
+        members: [head, adult_child]
+  output:
+    filing_status: SURVIVING_SPOUSE
+    basic_standard_deduction: 31_500
diff --git a/policyengine_us/tests/policy/baseline/household/demographic/tax_unit/surviving_spouse_eligible.yaml b/policyengine_us/tests/policy/baseline/household/demographic/tax_unit/surviving_spouse_eligible.yaml
index c84c6758396..9f0ef280682 100644
--- a/policyengine_us/tests/policy/baseline/household/demographic/tax_unit/surviving_spouse_eligible.yaml
+++ b/policyengine_us/tests/policy/baseline/household/demographic/tax_unit/surviving_spouse_eligible.yaml
@@ -2,7 +2,7 @@
   period: 2022
   input:
     people:
-      head: 
+      head:
         is_surviving_spouse: true
     tax_units:
       tax_unit:
@@ -14,14 +14,679 @@
   period: 2022
   input:
     people:
-      head: 
+      head:
         is_tax_unit_head: true
         is_surviving_spouse: true
-      child: {}
+      child:
+        age: 10
     tax_units:
       tax_unit:
         members: [head, child]
-        tax_unit_child_dependents: 1
         tax_unit_married: false
   output:
     surviving_spouse_eligible: true
+
+# IRC 2(a)(1)(B) determines the son or daughter's dependency "without regard
+# to subsections (b)(1), (b)(2), and (d)(1)(B)" of section 152. The 2025 Form
+# 1040 instructions (page 15) apply this as a child the filer "could claim as a
+# dependent except that ... the child had gross income of $5,200 or more".
+- name: Adult dependent child with gross income above the exemption amount still qualifies.
+  period: 2025
+  input:
+    people:
+      head:
+        age: 67
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      adult_child:
+        age: 29
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        # Above the $5,200 2025 qualifying relative gross income limit.
+        employment_income: 6_238
+    tax_units:
+      tax_unit:
+        members: [head, adult_child]
+  output:
+    dependent_gross_income: [0, 6_238]
+    is_qualifying_relative_dependent: [false, false]
+    surviving_spouse_eligible: true
+
+- name: Traced household, adult dependent child with $6,238 of disability benefits qualifies.
+  period: 2025
+  input:
+    people:
+      head:
+        age: 67
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      adult_child:
+        age: 29
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        disability_benefits: 6_238
+    tax_units:
+      tax_unit:
+        members: [head, adult_child]
+  output:
+    surviving_spouse_eligible: true
+
+- name: Adult dependent child with gross income at the exemption amount qualifies.
+  period: 2025
+  input:
+    people:
+      head:
+        age: 67
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      adult_child:
+        age: 29
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        employment_income: 5_200
+    tax_units:
+      tax_unit:
+        members: [head, adult_child]
+  output:
+    surviving_spouse_eligible: true
+
+- name: Adult dependent child with gross income below the exemption amount qualifies.
+  period: 2025
+  input:
+    people:
+      head:
+        age: 67
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      adult_child:
+        age: 29
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        employment_income: 3_000
+    tax_units:
+      tax_unit:
+        members: [head, adult_child]
+  output:
+    is_qualifying_relative_dependent: [false, true]
+    surviving_spouse_eligible: true
+
+- name: Permanently disabled adult child with high income qualifies.
+  period: 2025
+  input:
+    people:
+      head:
+        age: 67
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      adult_child:
+        age: 40
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        is_permanently_and_totally_disabled: true
+        employment_income: 20_000
+    tax_units:
+      tax_unit:
+        members: [head, adult_child]
+  output:
+    surviving_spouse_eligible: true
+
+# IRC 2(a)(1)(B)(i) requires a son, stepson, daughter or stepdaughter. A
+# dependent parent is a qualifying relative under IRC 152(d)(2)(C), but not a
+# child, so the filer does not qualify.
+- name: Dependent parent of the filer with income below the exemption amount does not qualify.
+  period: 2025
+  input:
+    people:
+      head:
+        age: 67
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      parent:
+        age: 88
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        is_parent_of_filer_or_spouse: true
+    tax_units:
+      tax_unit:
+        members: [head, parent]
+  output:
+    is_qualifying_relative_dependent: [false, true]
+    surviving_spouse_eligible: false
+
+- name: Dependent grandparent of the filer does not qualify.
+  period: 2025
+  input:
+    people:
+      head:
+        age: 50
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      grandparent:
+        age: 92
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        is_grandparent_of_filer_or_spouse: true
+    tax_units:
+      tax_unit:
+        members: [head, grandparent]
+  output:
+    surviving_spouse_eligible: false
+
+- name: Unrelated dependent member of the household does not qualify.
+  period: 2025
+  input:
+    people:
+      head:
+        age: 50
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      household_member:
+        age: 30
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        is_related_to_head_or_spouse: false
+    tax_units:
+      tax_unit:
+        members: [head, household_member]
+  output:
+    surviving_spouse_eligible: false
+
+- name: Dependent parent plus an adult child with high income qualifies through the child.
+  period: 2025
+  input:
+    people:
+      head:
+        age: 67
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      parent:
+        age: 88
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        is_parent_of_filer_or_spouse: true
+      adult_child:
+        age: 29
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        employment_income: 30_000
+    tax_units:
+      tax_unit:
+        members: [head, parent, adult_child]
+  output:
+    surviving_spouse_eligible: true
+
+- name: Remarried surviving spouse with a dependent child does not qualify.
+  period: 2025
+  input:
+    people:
+      head:
+        age: 67
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      spouse:
+        age: 65
+        is_tax_unit_head: false
+        is_tax_unit_spouse: true
+      child:
+        age: 10
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+    tax_units:
+      tax_unit:
+        members: [head, spouse, child]
+  output:
+    surviving_spouse_eligible: false
+
+- name: Filer who is not a surviving spouse does not qualify with an adult child.
+  period: 2025
+  input:
+    people:
+      head:
+        age: 67
+        is_tax_unit_head: true
+        is_surviving_spouse: false
+      adult_child:
+        age: 29
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        employment_income: 6_238
+    tax_units:
+      tax_unit:
+        members: [head, adult_child]
+  output:
+    surviving_spouse_eligible: false
+
+# Parent ids (natural, adoptive or step) identify the filer's own children.
+- name: Adult dependent whose parent id names the widowed head qualifies regardless of income.
+  period: 2025
+  input:
+    people:
+      head:
+        person_id: 1
+        age: 67
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      adult_child:
+        person_id: 2
+        parent_1_id: 1
+        age: 29
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        employment_income: 30_000
+    tax_units:
+      tax_unit:
+        members: [head, adult_child]
+    households:
+      household:
+        members: [head, adult_child]
+  output:
+    surviving_spouse_eligible: true
+
+- name: Dependent grandchild whose parent id names another household member does not qualify.
+  period: 2025
+  input:
+    people:
+      head:
+        person_id: 1
+        age: 60
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      mother:
+        person_id: 2
+        parent_1_id: 1
+        age: 35
+        is_tax_unit_head: true
+        is_tax_unit_spouse: false
+      grandchild:
+        person_id: 3
+        parent_1_id: 2
+        age: 8
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+    tax_units:
+      head_unit:
+        members: [head, grandchild]
+      mother_unit:
+        members: [mother]
+    households:
+      household:
+        members: [head, mother, grandchild]
+  output:
+    surviving_spouse_eligible: [false, false]
+
+- name: Dependent parent without parent ids in a household with ids does not qualify.
+  period: 2025
+  input:
+    people:
+      head:
+        person_id: 1
+        # The head's own parent id names the dependent mother.
+        parent_1_id: 2
+        age: 67
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      mother:
+        person_id: 2
+        age: 90
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        taxable_pension_income: 20_000
+    tax_units:
+      tax_unit:
+        members: [head, mother]
+    households:
+      household:
+        members: [head, mother]
+  output:
+    surviving_spouse_eligible: false
+
+# A parent id of 0 is unknown, not evidence that the filer is not the parent.
+- name: Head's own parent id does not stop a dependent child without ids from qualifying.
+  period: 2025
+  input:
+    people:
+      head:
+        person_id: 1
+        # Names the head's absent parent.
+        parent_1_id: 90
+        age: 67
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      adult_child:
+        person_id: 2
+        age: 29
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        employment_income: 3_000
+    tax_units:
+      tax_unit:
+        members: [head, adult_child]
+    households:
+      household:
+        members: [head, adult_child]
+  output:
+    surviving_spouse_eligible: true
+
+- name: Housemate's parent id in another tax unit does not stop a dependent child without ids from qualifying.
+  period: 2025
+  input:
+    people:
+      head:
+        person_id: 1
+        age: 67
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      adult_child:
+        person_id: 2
+        age: 29
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        employment_income: 3_000
+      housemate:
+        person_id: 3
+        parent_1_id: 90
+        age: 40
+        is_tax_unit_head: true
+        is_tax_unit_spouse: false
+    tax_units:
+      head_unit:
+        members: [head, adult_child]
+      housemate_unit:
+        members: [housemate]
+    households:
+      household:
+        members: [head, adult_child, housemate]
+  output:
+    surviving_spouse_eligible: [true, false]
+
+- name: Dependent child naming only the deceased parent, with the other id unknown, qualifies.
+  period: 2025
+  input:
+    people:
+      head:
+        person_id: 1
+        age: 67
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      adult_child:
+        person_id: 2
+        # The deceased spouse, who resolves to no household member.
+        parent_1_id: 91
+        age: 29
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        employment_income: 30_000
+    tax_units:
+      tax_unit:
+        members: [head, adult_child]
+    households:
+      household:
+        members: [head, adult_child]
+  output:
+    surviving_spouse_eligible: true
+
+- name: Dependent child whose second parent id names the head qualifies.
+  period: 2025
+  input:
+    people:
+      head:
+        person_id: 1
+        age: 67
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      adult_child:
+        person_id: 2
+        parent_1_id: 91
+        parent_2_id: 1
+        age: 29
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        employment_income: 30_000
+    tax_units:
+      tax_unit:
+        members: [head, adult_child]
+    households:
+      household:
+        members: [head, adult_child]
+  output:
+    surviving_spouse_eligible: true
+
+# Two parent ids can name both biological parents and leave out a step
+# parent, so naming two other parents does not rule a dependent out.
+- name: Stepchild whose two parent ids name absent biological parents qualifies.
+  period: 2025
+  input:
+    people:
+      head:
+        person_id: 1
+        age: 67
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      stepchild:
+        person_id: 2
+        # The deceased spouse and the child's other biological parent.
+        parent_1_id: 91
+        parent_2_id: 92
+        age: 15
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+    tax_units:
+      tax_unit:
+        members: [head, stepchild]
+    households:
+      household:
+        members: [head, stepchild]
+  output:
+    surviving_spouse_eligible: true
+
+- name: Daughter naming only her co-resident mother, with the other id unknown, qualifies her widowed father.
+  period: 2025
+  input:
+    people:
+      head:
+        person_id: 1
+        age: 45
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      daughter:
+        person_id: 2
+        parent_1_id: 3
+        age: 15
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+      mother:
+        person_id: 3
+        age: 40
+        is_tax_unit_head: true
+        is_tax_unit_spouse: false
+    tax_units:
+      head_unit:
+        members: [head, daughter]
+      mother_unit:
+        members: [mother]
+    households:
+      household:
+        members: [head, daughter, mother]
+  output:
+    surviving_spouse_eligible: [true, false]
+
+- name: Dependent nephew whose parent shares a parent id with the head does not qualify.
+  period: 2025
+  input:
+    people:
+      head:
+        person_id: 1
+        # The head's absent mother.
+        parent_1_id: 90
+        age: 50
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      nephew:
+        person_id: 2
+        parent_1_id: 3
+        age: 15
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+      sister:
+        person_id: 3
+        parent_1_id: 90
+        age: 45
+        is_tax_unit_head: true
+        is_tax_unit_spouse: false
+    tax_units:
+      head_unit:
+        members: [head, nephew]
+      sister_unit:
+        members: [sister]
+    households:
+      household:
+        members: [head, nephew, sister]
+  output:
+    surviving_spouse_eligible: [false, false]
+
+- name: Dependent sibling who shares an absent parent id with the head does not qualify.
+  period: 2025
+  input:
+    people:
+      head:
+        person_id: 1
+        parent_1_id: 90
+        age: 45
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      sibling:
+        person_id: 2
+        parent_1_id: 90
+        age: 30
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+    tax_units:
+      tax_unit:
+        members: [head, sibling]
+    households:
+      household:
+        members: [head, sibling]
+  output:
+    surviving_spouse_eligible: false
+
+- name: Dependent sibling who shares a co-resident parent with the head does not qualify.
+  period: 2025
+  input:
+    people:
+      head:
+        person_id: 1
+        parent_1_id: 3
+        age: 45
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      sibling:
+        person_id: 2
+        parent_1_id: 3
+        age: 30
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+      mother:
+        person_id: 3
+        age: 70
+        is_tax_unit_head: true
+        is_tax_unit_spouse: false
+    tax_units:
+      head_unit:
+        members: [head, sibling]
+      mother_unit:
+        members: [mother]
+    households:
+      household:
+        members: [head, sibling, mother]
+  output:
+    surviving_spouse_eligible: [false, false]
+
+- name: Dependent parent and grandparent named through the head's own parent ids do not qualify.
+  period: 2025
+  input:
+    people:
+      head:
+        person_id: 1
+        parent_1_id: 2
+        age: 50
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      mother:
+        person_id: 2
+        parent_1_id: 3
+        age: 75
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+      grandmother:
+        person_id: 3
+        age: 95
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+    tax_units:
+      tax_unit:
+        members: [head, mother, grandmother]
+    households:
+      household:
+        members: [head, mother, grandmother]
+  output:
+    surviving_spouse_eligible: false
+
+- name: Dependent grandmother linked through a mother in another tax unit does not qualify.
+  period: 2025
+  input:
+    people:
+      head:
+        person_id: 1
+        parent_1_id: 2
+        age: 45
+        is_tax_unit_head: true
+        is_surviving_spouse: true
+      mother:
+        person_id: 2
+        parent_1_id: 3
+        age: 75
+        is_tax_unit_head: true
+        is_tax_unit_spouse: false
+      grandmother:
+        person_id: 3
+        age: 95
+        is_tax_unit_head: false
+        is_tax_unit_spouse: false
+        is_tax_unit_dependent: true
+        taxable_pension_income: 20_000
+    tax_units:
+      head_unit:
+        members: [head, grandmother]
+      mother_unit:
+        members: [mother]
+    households:
+      household:
+        members: [head, mother, grandmother]
+  output:
+    surviving_spouse_eligible: [false, false]
diff --git a/policyengine_us/tests/policy/baseline/household/demographic/tax_unit/test_surviving_spouse_eligible_properties.py b/policyengine_us/tests/policy/baseline/household/demographic/tax_unit/test_surviving_spouse_eligible_properties.py
new file mode 100644
index 00000000000..71cb8f97c72
--- /dev/null
+++ b/policyengine_us/tests/policy/baseline/household/demographic/tax_unit/test_surviving_spouse_eligible_properties.py
@@ -0,0 +1,258 @@
+"""Exhaustive property checks for surviving spouse filing status.
+
+The relationship examples live in surviving_spouse_eligible.yaml and
+filing_status.yaml. These tests check invariants over every combination on
+the grid below, which named YAML cases cannot state: eligibility never
+changes with the dependent's income (units grouped by everything but
+income), matches a reference rule written from the grid's relationship
+labels, and differs from the previous rule (read from
+tax_unit_child_dependents) only for children who fail the gross income test.
+Every combination is its own tax unit in one vectorized simulation on the
+shared model, so mixed populations are exercised too.
+
+IRC 2(a)(1)(B) requires a dependent son, stepson, daughter or stepdaughter,
+with dependency determined without regard to IRC 152(b)(1), (b)(2) and
+(d)(1)(B), so the qualifying relative gross income test does not apply.
+"""
+
+import itertools
+
+import numpy as np
+import pytest
+
+from policyengine_us import Simulation
+from policyengine_us.system import system
+
+PERIOD = 2025
+EXEMPTION_AMOUNT = system.parameters(PERIOD).gov.irs.income.exemption.amount
+
+SURVIVING_SPOUSE = [True, False]
+MARRIED = [False, True]
+# Under 19 (qualifying child by age), an adult child, an elderly relative.
+AGES = [10, 29, 88]
+INCOMES = [0, 3_000, EXEMPTION_AMOUNT - 1, EXEMPTION_AMOUNT, 6_238, 50_000]
+DISABLED = [False, True]
+# How the dependent's relationship to the head is described, and whether it
+# makes the dependent the head's child. A parent id of 0 is unknown. "Other"
+# is a relative who lives in the household and files in their own tax unit.
+RELATIONSHIPS = {
+    # No parent ids and no relationship flags.
+    "unmarked": True,
+    # Relationship flags without parent ids.
+    "parent": False,
+    "grandparent": False,
+    "unrelated": False,
+    # The dependent's first id names the head.
+    "names_head": True,
+    # The dependent's first id names an absent parent; the second is unknown.
+    "names_absent_parent_only": True,
+    # Two absent parents named: the head can still be a step parent.
+    "names_two_absent_parents": True,
+    # The dependent names the other, who has no ids: the head can still be
+    # the second parent.
+    "names_other": True,
+    # The head's own id names an absent parent; the dependent has no ids.
+    "head_has_ids": True,
+    # The head's own id names the dependent.
+    "named_as_head_parent": False,
+    # The head and the dependent name the same absent parent.
+    "shares_parent_with_head": False,
+    # The dependent names the other, whose id names the head.
+    "parent_names_head": False,
+    # The dependent names the other, who shares an absent parent with the head.
+    "parent_shares_parent_with_head": False,
+}
+NEEDS_OTHER = {"names_other", "parent_names_head", "parent_shares_parent_with_head"}
+
+UNITS = [
+    dict(
+        surviving=surviving,
+        married=married,
+        age=age,
+        income=income,
+        disabled=disabled,
+        relationship=relationship,
+    )
+    for surviving, married, age, income, disabled, relationship in itertools.product(
+        SURVIVING_SPOUSE, MARRIED, AGES, INCOMES, DISABLED, RELATIONSHIPS
+    )
+] + [
+    dict(surviving=surviving, married=married, relationship=None)
+    for surviving in SURVIVING_SPOUSE
+    for married in MARRIED
+]
+# Ids that name no one in the simulation.
+ABSENT_ID = 10_000_000
+
+
+def _situation():
+    year = str(PERIOD)
+    people, tax_units, marital_units, households = {}, {}, {}, {}
+    for i, unit in enumerate(UNITS):
+        head, spouse, dependent, other = (f"{r}_{i}" for r in ("h", "s", "d", "o"))
+        head_id, spouse_id, dependent_id, other_id = (4 * i + k for k in (1, 2, 3, 4))
+        absent_id, second_absent_id = ABSENT_ID + 2 * i, ABSENT_ID + 2 * i + 1
+        members = [head]
+        people[head] = {
+            "person_id": {year: head_id},
+            "age": {year: 67},
+            "is_tax_unit_head": {year: True},
+            "is_tax_unit_spouse": {year: False},
+            "is_surviving_spouse": {year: unit["surviving"]},
+        }
+        if unit["married"]:
+            members.append(spouse)
+            people[spouse] = {
+                "person_id": {year: spouse_id},
+                "age": {year: 65},
+                "is_tax_unit_head": {year: False},
+                "is_tax_unit_spouse": {year: True},
+            }
+        marital_units[f"m_{i}"] = {"members": members[:]}
+        tax_units[f"t_{i}"] = {"members": members}
+        households[f"g_{i}"] = {"members": members[:]}
+        relationship = unit["relationship"]
+        if relationship is None:
+            continue
+        members.append(dependent)
+        households[f"g_{i}"]["members"].append(dependent)
+        parent_ids = {
+            "names_head": (head_id, 0),
+            "names_absent_parent_only": (absent_id, 0),
+            "names_two_absent_parents": (absent_id, second_absent_id),
+            "shares_parent_with_head": (absent_id, 0),
+        }.get(relationship, (other_id, 0) if relationship in NEEDS_OTHER else (0, 0))
+        people[dependent] = {
+            "person_id": {year: dependent_id},
+            "parent_1_id": {year: parent_ids[0]},
+            "parent_2_id": {year: parent_ids[1]},
+            "age": {year: unit["age"]},
+            "is_tax_unit_head": {year: False},
+            "is_tax_unit_spouse": {year: False},
+            "is_tax_unit_dependent": {year: True},
+            "employment_income": {year: unit["income"]},
+            "is_permanently_and_totally_disabled": {year: unit["disabled"]},
+            "is_parent_of_filer_or_spouse": {year: relationship == "parent"},
+            "is_grandparent_of_filer_or_spouse": {year: relationship == "grandparent"},
+            "is_related_to_head_or_spouse": {year: relationship != "unrelated"},
+        }
+        marital_units[f"dm_{i}"] = {"members": [dependent]}
+        head_parent_id = {
+            "head_has_ids": absent_id,
+            "named_as_head_parent": dependent_id,
+            "shares_parent_with_head": absent_id,
+            "parent_shares_parent_with_head": absent_id,
+        }.get(relationship)
+        if head_parent_id is not None:
+            people[head]["parent_1_id"] = {year: head_parent_id}
+        if relationship in NEEDS_OTHER:
+            other_parent_id = {
+                "parent_names_head": head_id,
+                "parent_shares_parent_with_head": absent_id,
+            }.get(relationship, 0)
+            people[other] = {
+                "person_id": {year: other_id},
+                "parent_1_id": {year: other_parent_id},
+                "age": {year: 40},
+                "is_tax_unit_head": {year: True},
+                "is_tax_unit_spouse": {year: False},
+            }
+            marital_units[f"om_{i}"] = {"members": [other]}
+            tax_units[f"ot_{i}"] = {"members": [other]}
+            households[f"g_{i}"]["members"].append(other)
+
+    def copy(groups):
+        return {name: {"members": g["members"][:]} for name, g in groups.items()}
+
+    return {
+        "people": people,
+        "tax_units": tax_units,
+        "marital_units": marital_units,
+        "spm_units": copy(households),
+        "families": copy(households),
+        "households": households,
+    }
+
+
+def _field(name, default):
+    return np.array([unit.get(name, default) for unit in UNITS])
+
+
+@pytest.fixture(scope="module")
+def grid():
+    sim = Simulation(situation=_situation())
+    position = {name: i for i, name in enumerate(sim.populations["tax_unit"].ids)}
+    order = [position[f"t_{i}"] for i in range(len(UNITS))]
+
+    def calc(variable):
+        return np.asarray(sim.calculate(variable, PERIOD))[order]
+
+    return {
+        "eligible": calc("surviving_spouse_eligible"),
+        "hoh": calc("head_of_household_eligible"),
+        "filing_status": sim.calculate("filing_status", PERIOD).decode_to_str()[order],
+        "child_dependents": calc("tax_unit_child_dependents"),
+        "surviving": _field("surviving", False),
+        "married": _field("married", False),
+        "has_dependent": np.array([u["relationship"] is not None for u in UNITS]),
+        "is_child": np.array(
+            [RELATIONSHIPS.get(u["relationship"], False) for u in UNITS]
+        ),
+        "age": _field("age", -1),
+        "income": _field("income", -1),
+        "disabled": _field("disabled", False),
+    }
+
+
+def test_matches_reference_rule(grid):
+    # A surviving spouse head, not remarried, with a dependent child.
+    expected = grid["surviving"] & ~grid["married"] & grid["is_child"]
+    assert len(grid["eligible"]) == len(UNITS)
+    np.testing.assert_array_equal(grid["eligible"], expected)
+
+
+def test_dependent_income_never_changes_eligibility(grid):
+    groups = {}
+    for i, unit in enumerate(UNITS):
+        if unit["relationship"] is not None:
+            key = tuple(value for name, value in unit.items() if name != "income")
+            groups.setdefault(key, set()).add(bool(grid["eligible"][i]))
+    assert len(groups) * len(INCOMES) == grid["has_dependent"].sum()
+    assert all(len(values) == 1 for values in groups.values())
+
+
+def test_non_child_dependents_never_qualify(grid):
+    not_child = grid["has_dependent"] & ~grid["is_child"]
+    assert not_child.any()
+    assert not grid["eligible"][not_child].any()
+
+
+def test_eligibility_requires_unmarried_surviving_spouse_with_dependent(grid):
+    eligible = grid["eligible"]
+    assert eligible.any()
+    assert (~grid["has_dependent"]).sum() == len(SURVIVING_SPOUSE) * len(MARRIED)
+    assert grid["surviving"][eligible].all()
+    assert not grid["married"][eligible].any()
+    assert grid["has_dependent"][eligible].all()
+
+
+def test_filing_status_follows_eligibility(grid):
+    eligible = grid["eligible"]
+    np.testing.assert_array_equal(grid["filing_status"] == "SURVIVING_SPOUSE", eligible)
+    assert not (eligible & grid["hoh"]).any()
+
+
+def test_only_change_for_children_is_dropping_income_test(grid):
+    # Differential against the previous rule, which counted child dependents
+    # under is_child_dependent and so applied the gross income test.
+    previous = grid["surviving"] & ~grid["married"] & (grid["child_dependents"] > 0)
+    is_child = grid["is_child"]
+    # Every child unit the previous rule accepted stays eligible.
+    assert grid["eligible"][previous & is_child].all()
+    # Units added are adult, non-disabled children whose income fails the
+    # qualifying relative gross income test.
+    added = grid["eligible"] & ~previous
+    assert added.any()
+    assert (grid["age"][added] >= 19).all()
+    assert not grid["disabled"][added].any()
+    assert (grid["income"][added] >= EXEMPTION_AMOUNT).all()
diff --git a/policyengine_us/variables/household/demographic/tax_unit/surviving_spouse_eligible.py b/policyengine_us/variables/household/demographic/tax_unit/surviving_spouse_eligible.py
index 01ef59677b2..abf7e783058 100644
--- a/policyengine_us/variables/household/demographic/tax_unit/surviving_spouse_eligible.py
+++ b/policyengine_us/variables/household/demographic/tax_unit/surviving_spouse_eligible.py
@@ -1,4 +1,8 @@
 from policyengine_us.model_api import *
+from policyengine_us.variables.household.demographic.person._parent_links import (
+    co_resident_parent_indices,
+    tax_unit_parent_indices,
+)
 
 
 class surviving_spouse_eligible(Variable):
@@ -6,7 +10,29 @@ class surviving_spouse_eligible(Variable):
     entity = TaxUnit
     definition_period = YEAR
     label = "Qualifies for surviving spouse filing status"
-    reference = "https://www.law.cornell.edu/uscode/text/26/2#a"
+    documentation = (
+        "IRC 2(a)(1)(B) requires a dependent son, stepson, daughter or "
+        "stepdaughter, with dependency determined without regard to IRC "
+        "152(b)(1), (b)(2) and (d)(1)(B). The qualifying relative gross "
+        "income test of 152(d)(1)(B) does not apply, so an adult child with "
+        "gross income at or above the exemption amount still qualifies the "
+        "filer. A dependent is the head's child when their parent_1_id or "
+        "parent_2_id (natural, adoptive or step parents) names the tax unit "
+        "head. Because a parent id of 0 is unknown and a person can have more "
+        "parents than the two ids hold, naming other parents does not rule a "
+        "dependent out. The ids rule a dependent out only when they show "
+        "another relationship to the head: the head's parent or grandparent, "
+        "a sibling (a shared parent id), a grandchild (the dependent's parent "
+        "names the head) or a niece or nephew (the dependent's parent shares "
+        "a parent id with the head). Otherwise a dependent counts as the "
+        "head's child unless marked as a parent or grandparent of the filer "
+        "or as unrelated to the filer. Without such ids the model cannot tell "
+        "a child from a sibling, niece, nephew or grandchild."
+    )
+    reference = (
+        "https://www.law.cornell.edu/uscode/text/26/2#a_1_B",
+        "https://www.irs.gov/pub/irs-pdf/i1040gi.pdf#page=15",
+    )
 
     def formula(tax_unit, period, parameters):
         # The surviving spouse filing status should only apply to surviving spouse heads
@@ -15,6 +41,72 @@ def formula(tax_unit, period, parameters):
         is_head = person("is_tax_unit_head", period)
         is_surviving_spouse = person("is_surviving_spouse", period)
         surviving_spouse_head = tax_unit.any(is_head & is_surviving_spouse)
-        has_child_dependents = tax_unit("tax_unit_child_dependents", period) > 0
+        # Without the 152(d)(1)(B) gross income test, the qualifying child,
+        # disabled dependent and qualifying relative paths of
+        # is_child_dependent together cover every tax unit dependent.
+        is_dependent = person("is_tax_unit_dependent", period)
+
+        # IRC 2(a)(1)(B)(i) limits the dependent to a son, stepson, daughter
+        # or stepdaughter of the filer. Each person's parents, as rows: both
+        # id slots resolved among household members and among tax unit
+        # members, -1 when unresolved.
+        rows = np.arange(person.count)
+        parent_rows = [
+            *co_resident_parent_indices(person, period),
+            *tax_unit_parent_indices(person, period),
+        ]
+        parent_ids = [person("parent_1_id", period), person("parent_2_id", period)]
+
+        def parents_of(of):
+            safe = np.maximum(of, 0)
+            return [where(of >= 0, parent[safe], -1) for parent in parent_rows]
+
+        def ids_of(of):
+            safe = np.maximum(of, 0)
+            return [where(of >= 0, ids[safe], 0) for ids in parent_ids]
+
+        def shares_id(ids, other_ids):
+            shared = np.zeros(person.count, dtype=bool)
+            for a in ids:
+                for b in other_ids:
+                    shared |= (a != 0) & (a == b)
+            return shared
+
+        # Row of the head of each person's tax unit.
+        unit = person.tax_unit.reference_entity.members_entity_id
+        head_by_unit = np.full(tax_unit.count, -1)
+        head_by_unit[unit[is_head]] = rows[is_head]
+        head = head_by_unit[unit]
+        head_parents = parents_of(head)
+        head_ids = ids_of(head)
+
+        names_head = np.zeros(person.count, dtype=bool)
+        is_head_grandchild = np.zeros(person.count, dtype=bool)
+        is_head_niece_or_nephew = np.zeros(person.count, dtype=bool)
+        for parent in parent_rows:
+            names_head |= (head >= 0) & (parent == head)
+            for grandparent in parents_of(parent):
+                is_head_grandchild |= (head >= 0) & (grandparent == head)
+            is_head_niece_or_nephew |= (parent >= 0) & shares_id(
+                ids_of(parent), head_ids
+            )
+        is_head_ancestor = np.zeros(person.count, dtype=bool)
+        for parent in head_parents:
+            is_head_ancestor |= parent == rows
+            for grandparent in parents_of(parent):
+                is_head_ancestor |= grandparent == rows
+        is_head_sibling = shares_id(parent_ids, head_ids)
+
+        not_child = (
+            is_head_ancestor
+            | is_head_sibling
+            | is_head_grandchild
+            | is_head_niece_or_nephew
+            | person("is_parent_of_filer_or_spouse", period)
+            | person("is_grandparent_of_filer_or_spouse", period)
+            | ~person("is_related_to_head_or_spouse", period)
+        )
+        is_child = names_head | ~not_child
+        has_qualifying_child = tax_unit.any(is_dependent & is_child)
         married = tax_unit("tax_unit_married", period)
-        return surviving_spouse_head & has_child_dependents & ~married
+        return surviving_spouse_head & has_qualifying_child & ~married