Track B G/R2: decide the open readings

docs/design/track_b_g_conformance_report.json

@@ -750,7 +750,7 @@
         "status": "refused"
       },
       {
-        "description": "Two potential parents; one own RIB 780 lies between 75% and 82.5% of PIA 1000",
+        "description": "Two potential parents; own RIBs 780 and 790 both lie between 75% and 82.5% of PIA 1000",
         "id": "parent_benefit",
         "reason": "parent_benefit",
         "status": "refused"

scripts/track_b_g_conformance_report.py

@@ -445,7 +445,7 @@ def multiple_records(child):
             ),
         ),
         reasons.PARENT_BENEFIT: (
-            "Two potential parents; one own RIB 780 lies between 75% and 82.5% of PIA 1000",
+            "Two potential parents; own RIBs 780 and 790 both lie between 75% and 82.5% of PIA 1000",
             lambda: _family(
                 _survivor(),
                 [
@@ -454,7 +454,11 @@ def multiple_records(child):
                         g.Role.PARENT,
                         own_benefit=g.OwnBenefit(rib, F(780)),
                     ),
-                    g.Beneficiary("p2", g.Role.PARENT),
+                    g.Beneficiary(
+                        "p2",
+                        g.Role.PARENT,
+                        own_benefit=g.OwnBenefit(rib, F(790)),
+                    ),
                 ],
             ),
         ),

src/populace_dynamics/track_b/gross_benefits.py

@@ -1012,6 +1012,7 @@ def statutory_rates(params: SSAParameters) -> StatutoryRates:
         _input_type(getattr(params, name), int, name)
         if getattr(params, name) != 36:
             raise InvalidFamilyInput(f"{name} must be 36 (402(q))")
+    # Source conflict us:oasdi-reduction-exact-fractions
     return _construct_declared(
         StatutoryRates,
         worker_first=_STATUTE["worker_first"],
@@ -1118,6 +1119,7 @@ def disability_family_maximum(pia: object, aime: object) -> Fraction:
     earnings = _exact(aime, "AIME")
     if earnings < 0 or earnings.denominator != 1:
         raise InvalidFamilyInput("AIME must be a nonnegative whole dollar")
+    # Source conflict us:oasdi-disability-family-maximum-rounding
     return _floor_dime_validated(
         min(max(_DI_AIME_SHARE * earnings, amount), _DI_PIA_CAP * amount)
     )
@@ -3331,18 +3333,33 @@ class _Row:
     counted: Fraction = Fraction(0)
     mother_father_rate: Fraction = Fraction(0)
     note: str = ""
+    dwb_under_60: bool = False
 
     @property
     def dual(self) -> bool:
         return self.own_mba is not None
 
 
+def _dwb_under_60(beneficiary: Beneficiary, payment_month: YearMonth) -> bool:
+    """A DWB month in which the SSA birth cohort cannot yet have attained 60.
+
+    Cohort Y (born January 2, Y through January 1, Y+1) attains 60 during
+    Y+60, so every month of Y+59 and earlier is under 60. Months of Y+60
+    depend on the unsupplied birth month and are not treated as under 60.
+    """
+    return (
+        beneficiary.role is Role.DISABLED_WIDOW
+        and beneficiary.birth_year is not None
+        and payment_month.year <= beneficiary.birth_year + 59
+    )
+
+
 def _is_entitled(
     beneficiary: Beneficiary,
     pia: Fraction,
     own_mba: Fraction | None,
     *,
-    parent_ob: Fraction | None = None,
+    parent_threshold: Fraction | None = None,
 ) -> tuple[bool, str]:
     own = beneficiary.own_benefit
     if own is None:
@@ -3362,9 +3379,11 @@ def _is_entitled(
     if (
         beneficiary.role is Role.PARENT
         and own.kind is OwnBenefitKind.OLD_AGE
-        and own_mba >= parent_ob
+        and own_mba >= parent_threshold
     ):
-        return False, "own RIB not less than parent's OB (RS 00209.001)"
+        return False, (
+            "own RIB not less than the 402(h)(1)(D) share of the PIA"
+        )
     if (
         beneficiary.role is Role.MOTHER_FATHER
         and own.kind is OwnBenefitKind.OLD_AGE
@@ -3466,7 +3485,8 @@ def _parisi_counted(
 
     The own-RIB reduction is not an auxiliary age reduction (GN
     02603.060B.2: $2.40 payable + $0.90 reduction, not the $16 own-RIB
-    reduction). GN 02603.050A.2 disregards a dual rate reduced to zero.
+    reduction). GN 02603.050A.2 disregards a dual rate that is zero before
+    age reduction; a zero reached only after it counts the age reduction.
     Own delayed credits and redistribution with an actually limiting
     RIB-LIM remain refused: none of the captured worked cases settles
     those interacting amounts. A considered but nonlimiting RIB-LIM
@@ -3509,17 +3529,14 @@ def _parisi_counted(
     )
     if payable == 0:
         before_age = row.standard - (own.pia if method_c else row.own_mba)
+        # GN 02603.050A.2 disregards a rate that dual entitlement, considered
+        # first, reduces to zero (.045; .060 A.8). A zero reached only after
+        # the auxiliary's age reduction keeps that reduction in PTAP: only
+        # the amount withheld for dual entitlement in 402(k)(3)(A)'s order is
+        # redistributed (20 CFR 404.403(a)(5), 404.407(a); .060 B.2).
         # Source conflict us:oasdi-dual-entitlement-zero-after-age-reduction
-        if before_age > 0:
-            raise _computed(
-                FamilyConfigurationUnsupported,
-                UnsupportedReason.PARISI_AMBIGUOUS,
-                "dual payable reaches zero only after auxiliary age reduction: "
-                "GN 02603.045's before-age rule and GN 02603.050A.2's zero-rate "
-                "exception do not settle whether the age amount stays in PTAP",
-                beneficiary_id=beneficiary.beneficiary_id,
-            )
-        return Fraction(0), Fraction(0)
+        if before_age <= 0:
+            return Fraction(0), Fraction(0)
     if method_c:
         excess = max(Fraction(0), row.standard - own.pia)
         age_reduction = excess - _spouse_age_reduced_validated(
@@ -3563,6 +3580,12 @@ def _refuse_historical_auxiliary(
         if isinstance(beneficiary.child_in_care, str):
             return
     elif role is Role.DISABLED_WIDOW:
+        # Source conflict us:oasdi-dwb-1984-pre-1978-history
+        # RS 00615.301B.1.e: "all disabled widow(er)s under age 60 receive
+        # .715 of the full unreduced WIB for 1/84 and later", whatever the
+        # entitlement date; .005C.2's money history governs only from 60.
+        if row.dwb_under_60:
+            return
         first_age = 50
     elif role in _AGED_WIDOW_ROLES:
         first_age = 50
@@ -3582,6 +3605,7 @@ def _refuse_historical_auxiliary(
     own = beneficiary.own_benefit
     low, high = Fraction(0), row.rate
     if role in (Role.SPOUSE, Role.DIVORCED_SPOUSE):
+        # Source conflict us:oasdi-dual-entitlement-pre-1978-history
         if own is not None and beneficiary.own_benefit_first:
             excess = max(Fraction(0), row.rate - own.pia)
             high = max(Fraction(0), row.rate - (own.pia - row.own_base))
@@ -3837,16 +3861,44 @@ def _check_family_inputs(
     return beneficiaries
 
 
+def _parent_entitlement_thresholds(pia: Fraction) -> tuple[Fraction, Fraction]:
+    """402(h)(1)(D): 82.5 and 75 percent of the PIA, unrounded."""
+    return pia * Fraction(165, 200), pia * Fraction(3, 4)
+
+
+def _parent_threshold(
+    pia: Fraction, parents: tuple[int, frozenset[str]], beneficiary_id: str
+) -> Fraction:
+    """One parent's 402(h)(1)(D) own-RIB threshold in the resolved set.
+
+    ``parents`` is ``_entitled_parent_count``'s (count, excluded ids). An
+    entitled parent is tested at its own rate; an excluded parent at the
+    two-parent rate it would share.
+    """
+    parent_count, excluded = parents
+    one_rate, two_rate = _parent_entitlement_thresholds(pia)
+    if parent_count == 2 or beneficiary_id in excluded:
+        return two_rate
+    return one_rate
+
+
 def _entitled_parent_count(
     state: RecordState,
     beneficiaries: Sequence[Beneficiary],
     params: SSAParameters,
-) -> int:
-    """Resolve 402(h)(2)'s count, refusing the circular RIB threshold.
-
-    RS 00209.001 excludes a parent whose own RIB is not less than the
-    parent's benefit; RS 00209.015 counts an own-DIB parent as technically
-    entitled. More than two declared parents needs a separate rule.
+) -> tuple[int, frozenset[str]]:
+    """Resolve 402(h)(2)'s count and the parents (h)(1)(D) excludes.
+
+    402(h)(1)(D) tests an own RIB against 82.5 percent of the PIA when the
+    parent's benefit "is determinable under paragraph (2)(A)", and against
+    75 percent "in any other case". The entitled set must satisfy that test
+    for every parent at once: each entitled parent at its own rate, and
+    each excluded potential parent at the rate it would share. RS
+    00209.015 counts an own-DIB parent as technically entitled. The
+    thresholds are the unrounded percentages of the PIA that (h)(1)(D)
+    names, not the dime-floored OBs. Returns the count and the ids excluded
+    at the two-parent rate. More than two declared parents needs a
+    separate rule.
     """
     parents = [b for b in beneficiaries if b.role is Role.PARENT]
     if len(parents) > 2:
@@ -3856,12 +3908,7 @@ def _entitled_parent_count(
             "more than two declared parents is outside the one/two-parent "
             "rates settled by 402(h)(2) and RS 00209.015",
         )
-    one_ob = _original_benefit_validated(
-        Role.PARENT, FamilyKind.SURVIVOR, state.pia
-    )
-    two_ob = _original_benefit_validated(
-        Role.PARENT, FamilyKind.SURVIVOR, state.pia, parent_count=2
-    )
+    one_rate, two_rate = _parent_entitlement_thresholds(state.pia)
     potential = []
     for parent in parents:
         own = parent.own_benefit
@@ -3871,26 +3918,31 @@ def _entitled_parent_count(
             else _own_monthly_benefit_validated(own, params)[1]
         )
         if own is not None and own.kind is OwnBenefitKind.OLD_AGE:
-            if own_mba >= one_ob:
+            if own_mba >= one_rate:
                 continue
         potential.append((parent, own_mba))
-    if len(potential) == 2:
-        for parent, own_mba in potential:
-            # Source conflict us:oasdi-parent-entitlement-count-interval
-            if (
-                parent.own_benefit is not None
-                and parent.own_benefit.kind is OwnBenefitKind.OLD_AGE
-                and own_mba >= two_ob
-            ):
-                raise _computed(
-                    FamilyConfigurationUnsupported,
-                    UnsupportedReason.PARENT_BENEFIT,
-                    "two potential parents with own RIB between the "
-                    "75% and 82.5% OBs have a circular entitlement count "
-                    "under RS 00209.001 and .015",
-                    beneficiary_id=parent.beneficiary_id,
-                )
-    return max(1, len(potential))
+    in_band = [
+        parent
+        for parent, own_mba in potential
+        if parent.own_benefit is not None
+        and parent.own_benefit.kind is OwnBenefitKind.OLD_AGE
+        and own_mba >= two_rate
+    ]
+    if len(potential) < 2 or not in_band:
+        return max(1, len(potential)), frozenset()
+    # Source conflict us:oasdi-parent-entitlement-count-interval
+    # A RIB in [75%, 82.5%) fails beside an entitled parent and passes
+    # alone. With one such parent, only "the other parent alone" satisfies
+    # 402(h)(1)(D) for both; with two, either parent alone does.
+    if len(in_band) == 2:
+        raise _computed(
+            FamilyConfigurationUnsupported,
+            UnsupportedReason.PARENT_BENEFIT,
+            "two parents with own RIB between 75% and 82.5% of the PIA: "
+            "402(h)(1)(D) is satisfied by either parent alone",
+            beneficiary_id=in_band[0].beneficiary_id,
+        )
+    return 1, frozenset({in_band[0].beneficiary_id})
 
 
 def _mother_father_care_rate(
@@ -4051,16 +4103,17 @@ def possible_drc_basis(member):
                 possible_count += 1
                 possible_widow |= possible_drc_basis(member)
                 continue
-            parent_count = (
+            parents = (
                 _entitled_parent_count(state, beneficiaries, params)
                 if member.role is Role.PARENT
-                else 1
+                else (1, frozenset())
             )
             row = _original_entitlement_rows(
                 state,
                 (_with_effective_cohort(member),),
                 params,
-                parent_count,
+                payment_month,
+                parents,
             )[0]
             subject = row.subject
         except FamilyConfigurationUnsupported:
@@ -4072,11 +4125,15 @@ def possible_drc_basis(member):
 
 
 def _original_entitlement_rows(
-    state, beneficiaries, params, parent_count=None
+    state, beneficiaries, params, payment_month, parents=None
 ):
-    """G's OB and own-benefit entitlement, before any family allocation."""
-    if parent_count is None:
-        parent_count = _entitled_parent_count(state, beneficiaries, params)
+    """G's OB and own-benefit entitlement, before any family allocation.
+
+    ``parents`` is ``_entitled_parent_count``'s (count, excluded ids) for
+    the whole roster; an excluded parent is tested at the two-parent rate.
+    """
+    if parents is None:
+        parents = _entitled_parent_count(state, beneficiaries, params)
     rows = []
     for beneficiary in beneficiaries:
         own_base = own_mba = None
@@ -4090,11 +4147,16 @@ def _original_entitlement_rows(
             state.pia,
             beneficiary.original_benefit_basis,
             parent_count=(
-                parent_count if beneficiary.role is Role.PARENT else None
+                parents[0] if beneficiary.role is Role.PARENT else None
             ),
         )
         entitled, note = _is_entitled(
-            beneficiary, state.pia, own_mba, parent_ob=ob
+            beneficiary,
+            state.pia,
+            own_mba,
+            parent_threshold=_parent_threshold(
+                state.pia, parents, beneficiary.beneficiary_id
+            ),
         )
         rows.append(
             _Row(
@@ -4105,6 +4167,7 @@ def _original_entitlement_rows(
                 own_base=own_base,
                 own_mba=own_mba,
                 note=note,
+                dwb_under_60=_dwb_under_60(beneficiary, payment_month),
             )
         )
     return rows
@@ -4187,7 +4250,7 @@ def _family_benefits(
             "IEDS before January 1985, or on a WEP-affected worker record "
             "before January 2024, is not implemented (RS 00202.100)",
         )
-    parent_count = _entitled_parent_count(state, beneficiaries, params)
+    parents = _entitled_parent_count(state, beneficiaries, params)
     life_case = state.kind is not FamilyKind.SURVIVOR and not ieds
     worker_benefit = None
     if _declared_worker_entitled(state):
@@ -4199,7 +4262,11 @@ def _family_benefits(
             worker_benefit = state.pia
 
     rows = _original_entitlement_rows(
-        state, beneficiaries, params, parent_count
+        state,
+        beneficiaries,
+        params,
+        payment_month,
+        parents,
     )
 
     _refuse_widow_drc_savings_clause(state, rows)
@@ -4861,6 +4928,7 @@ def _readjusted_for_events(
         ),
         Fraction(0),
     )
+    # Source conflict us:oasdi-nh-charge-age-reduction-interaction
     if reserve and any(row.age_reduction_factor != 1 for row in subject):
         raise _computed(
             FamilyConfigurationUnsupported,
@@ -5061,6 +5129,7 @@ def _readjust_deduction_rows(
                 standard=old.standard_rate,
                 rate=rate,
                 counted=rate,
+                dwb_under_60=_dwb_under_60(member, payment_month),
             )
             minimum = care_minimums.get(bid)
             if minimum is not None:
@@ -5744,6 +5813,7 @@ def _savings_payment(
         row for row in result.beneficiaries if row.subject_to_family_maximum
     ]
     reduced = [row for row in subject if row.age_reduction_factor < 1]
+    # Source conflict us:oasdi-saving-clause-procedure-gaps
     if (
         result.kind is FamilyKind.SURVIVOR
         or any(row.own_benefit is not None for row in subject)
@@ -6069,6 +6139,7 @@ def _operational_admit(
         total: Fraction,
     ) -> FamilyBenefits:
         membership = _savings_membership(result)
+        # Source conflict us:oasdi-saving-clause-procedure-gaps
         if (
             self._protected_membership is not None
             and membership != self._protected_membership