Count Colorado's in-kind support and maintenance for AND-CS clients in another person's household

[MaxGhenis]

Stacked on #10161 (base co-and-cs-payment-floor-3549), which is stacked on #10145. Review only the commits after 87281e2751 (rebased onto #10161's review-round-1 head). Merge waits on Max's ruling d1446 (which reading of the ISM amount; see "Readings").

Summary

Colorado counts in-kind support and maintenance (ISM) as unearned income of Old Age Pension and AND-CS clients (9 CCR 2503-5 3.520.79). Since March 2, 2014, an SSI recipient whom SSA charges ISM is charged "a matching ISM" (3.520.79(B)(6), 3.520.71(E)).

AND-CS counted only SSI's presumed maximum value (PMV), so an SSI recipient in another person's household got SSA's one-third reduction back in full: $331.33/month in 2026. With the matching ISM, that client's grant is $20/month.

• New co_ssa_in_kind_support_and_maintenance (Person, MONTH) is the ISM Colorado counts. AND-CS reads it now. OAP will read it once its income rewrite (Apply Colorado's OAP payment floor and count OAP income under 3.533-3.534 #10176) lands; that swap is a follow-up.
• New parameters under gov.states.co.ssa.ism:
  • maximum: the published monthly maximum, 2014-2026;
  • component_share.shelter and component_share.food: the pre-2014 caps.

What the sources say

Does Colorado count ISM for a client in another person's household? Yes. Every primary source says so, and has since at least 2003.

Source	What it says
9 CCR 2503-5 3.520.79 (2026, PDF pp. 72-74)	(A) "For certain clients who are not paying their fair share of shelter costs, an ISM amount shall be determined and counted as unearned income." (C)(3) "If the client is paying no shelter costs, and all shelter costs are supplied in full, then the current maximum ISM amount is counted." (B)(6) "A client is receiving SSI and being charged an ISM by the SSA. The client shall be charged a matching ISM for Adult Financial programs."
3.520.71(E) (p. 44)	"The county department shall deduct an identical ISM amount for Adult Financial programs until the SSA ISM is removed."
3.520.79 as first adopted (eff. 3/2/14, p. 43)	(D) "A client receiving SSI and being charged an ISM by the Social Security Administration (SSA) shall be charged a matching ISM." The current (B)(6) wording dates from 3/1/2020.
9 CCR 2503-2 3.250.22 (2012) and 9 CCR 2503-1 3.250.22 (the oldest version on the SOS site, with 2003 amendments)	ISM for OAP and AND/SSI-CS clients "not paying their fair share of housing costs ... counted as unearned income", capped at "the shelter and utility component" of the grant standard. Free shelter counts that maximum. 3.250.222 counts "in kind items, other than shelter and utilities, supplied in full at no cost" at their component.
AND/SSI-CS component tables: 2004, 2007, 2014	Shelter and utilities 37.0% (2004) and 36.6% (from 1/1/07) of the standard; food 20.5%. From 1/1/14 shelter is "33.33% of federal SSI grant standard + $20 disregard", $260, and there is no food component.
CDHS Adult Financial Reference Guide v11.0 (Dec 2025, pp. 3-4)	AND-CS serves customers "receiving an SSI payment that is less than the full SSI grant standard". "If SSA is charging the customer an ISM, we must charge a matching ISM in CBMS."
CDHS rulemaking packet 2025-00596 (p. 4)	"The SSA will increase the ISM for 2026 from $342 to $351 ($994 * 33.33% + 20 = 351.30). Colorado, as part of the pass-along agreement, matches the SSA's COLA which includes the application of an ISM to certain AF recipients. The ISM adjustment only impacts approximately 5% of the combined OAP and AND-CS caseload."
CCHN Adult Financial overview (July 2021, p. 7; not law)	AND-CS: "Clients who are not receiving maximum SSI benefits due to an ISM are not eligible."
SSA, State Assistance Programs for SSI Recipients, Colorado, 2002 through 2011 (every edition 2002, 2004-2011; secondary)	"Persons living in the household of another are included under the living independently standard; state supplement is increased to offset the reduced federal payment." The same pages say "Income exclusions: Federal SSI regulations apply".

SSA's sentence is the only source for full offset. Two things count against it. First, Colorado's rule text counted ISM in every version SSA's reports overlap. Second, the same pages describe Colorado's income rules as federal, which 3.549 and 3.250.22 contradict. The sentence reads as a description of the payment formula (standard − SSI − income), which does grow when SSI shrinks, before ISM is counted. #10161 kept the offset (its Case 28) and listed this as a follow-up.

Readings (Max: d1446)

The sources agree ISM is counted. They leave two defensible amounts for an SSI recipient on the one-third reduction:

Reading	ISM (2026)	AND-CS, single, no other income	AND-CS, SSI couple, each	Basis
(a) matching: SSA's ISM (implemented)	331.33	$20.00	$258.50	(B)(6) "matching ISM", 3.520.71(E) "identical ISM amount", 20 CFR 416.1131(a) "we count one-third of the Federal benefit rate as additional income"; consistent with how #10145 already matches a couple's PMV
(b) Colorado's maximum	351	$0.33, raised to the $13 floor	$156.00	(C)(3) "current maximum ISM amount"; CDHS's packet calls $351 SSA's ISM
(c) no ISM	0	$331.33	$497.00	SSA's 2002-2011 Colorado reports only

Under (a), SSA applies no income exclusion to the one-third reduction (416.1131(b)), but Colorado's $20 unearned disregard (3.549(A)(2)(c)) applies to the matched ISM like any other unearned income. The $20 grant is that disregard. With $20 or more of other unearned income, SSA uses its $20 exclusion and Colorado uses its own, and the grant is $0 (Case 33). For PMV clients, (a) and #10161 agree. For a single client, SSA's PMV of $351.33 less $20 offsets SSI's reduction exactly, and the grant stays $0. An SSI couple on the PMV keeps $248.50 each: 994 − 497 − (258.50 − 10).

(a) is recommended because (B)(6) and 3.520.71(E) address exactly this client (an SSI recipient whom SSA charges ISM) and speak to the amount; (C) is the general computation. Switching to (b) changes one line in _ssa_ism; the mutation check below confirms the tests catch it.

The model

Period	Who	ISM
2002 – 2006	—	not modeled (0); see the pre-2014 caveat
2007 – 2013	everyone not exempt	shelter: 36.6% of the AND-CS standard when others supply shelter; and, separately, food: 20.5% of the standard when others pay all meals
Jan – Feb 2014	everyone not exempt, receiving shelter from others	$260
Mar 2014 –	SSI recipients	SSA's ISM: one-third of the benefit rate under the one-third reduction, otherwise the PMV ISM (halved for a couple)
Mar 2014 –	others not exempt, receiving shelter from others	the published maximum ($351 in 2026)

• Exempt (3.520.79(B)(1)-(3); 3.250.22(A), (B), (G)): clients who own and live in their home (household tenure_type owned, not in another person's household), receive housing assistance, or are homeless. For SSI recipients charged ISM, (B)(6) overrides these ("unless").
• Medical confinement (3.520.786(B); 3.250.32 before 2014): room and board furnished during medical confinement is exempt when a third party pays, and isn't in-kind support when the client pays. A client in a medical treatment facility is counted no ISM.
• Inputs: Colorado's amount depends on what the client pays, not on what the shelter is worth: (C)(1) is the maximum less the payment; (C)(2) is the lesser of the fair share and the maximum, less the payment; (C)(3) is the maximum for a client paying nothing. PolicyEngine has no input for the payment, the fair share or the market value. So a client who receives shelter from others (the SSI living-arrangement inputs) is taken to pay none and is counted the maximum. ssi_shelter_support_value feeds only SSA's own ISM, which an SSI recipient's matching ISM follows.
• SSI recipients SSA doesn't charge: with PolicyEngine's inputs, SSA charges ISM whenever 3.520.79(C) would, except to a child whom SSI classifies as living in the parental household (an SSI-ineligible parent in the tax unit; SSI deems instead), or a medical-facility resident. So SSI recipients get SSA's ISM or none, and a child SSI deems from is not charged ISM.
• Maximum: the published amounts (3.530(B), 3.546(D)), not the formula in 3.520.79(E). They differ in 2021: $284 published, $285 by the formula.
• Pre-2014 caveats: the rule counted ISM from at least 2003. But the table effective January 1, 2004 (shelter 37.0%, food 20.5%) prints an AND/SSI-CS "maximum grant" of $513, while PE's grant standard (from SSA's reports) is $601. The components' base for 2002-2006 is therefore unsettled, and the model starts with the 2007 table (36.6%, 20.5%), whose base is the grant standard. Auditing the pre-2014 standards, then extending ISM back to 2002, is a separate follow-up. Shelter and food are independent: a client whose meals others pay counts the food component even without shelter support (2012 food alone: 20.5% of $698 = 143.09).
• Grant cents: 3.581(E) (p. 134) keeps cents when SSI reduces the grant, so the $0.33 in Jan-Feb 2014 is paid as is.

Worked cases (YAML)

Monthly unless noted. "Before" is #10161's head (87281e2751), computed.

Case	Before	After	Rule
2026, single, another's household (SSI 662.67)	$331.33	$20.00	994 − 662.67 − (331.33 − 20)
2026, same with SSDI $100 (SSI 582.67)	$331.33	$0	582.67 + 100 + 331.33 − 20 = 994: not eligible
2026, SSI couple, another's household (497 each)	$497.00 each	$258.50 each	994 − 497 − (248.50 − 10)
2026, single, outside shelter support (PMV)	$0	$0	unchanged
2025, single, another's household	$322.33	$20.00	967 − 644.67 − 302.33
2014 (year), single, another's household	$2,884/yr	$200.67/yr	Jan-Feb 721 − 480.67 − 240 = 0.33; Mar-Dec 20
2012, single, another's household	$232.67	$0	ISM 255.47 + 143.09 = 398.56

co_ssa_in_kind_support_and_maintenance.yaml (18 cases) covers:

• matching under the one-third reduction, under the PMV, and at a lower support value;
• couples;
• clients without SSI: the maximum (also when the shelter is worth less), subsidized housing, homeownership;
• an SSI homeowner, whom (B)(6) still charges;
• a child living with a parent;
• the 2014 switch, and 2012 and 2007 under the old components;
• a client in a medical facility (no ISM).

Invariants

policyengine_us/tests/core/test_co_ism_invariants.py checks Hypothesis-drawn SSI clients (single or couple, SSDI and earnings, either arrangement, a drawn support value), each beside a twin with no support, plus non-SSI clients aged 62, in 2026:

1. Matching (differential): an SSI recipient's ISM equals SSA's. Under the one-third reduction, that is the twins' difference in ssi_amount_if_eligible, a second implementation of the reduction. Otherwise it is SSI's PMV ISM, halved for a couple.
2. Bounds: 0 ≤ ISM, and ≤ the PMV with SSI.
3. No backfill: in-kind support lowers SSI + AND-CS by at least SSA's ISM, less the client's share of the $20 disregard, less any payment that raises a grant to the $13 floor. The review's counterexample (a couple earning $1,145 and $106 a month, whose supported spouse's $10 grant is raised to $13) is pinned as a Hypothesis example.
4. Payment, not value: a client without SSI who receives shelter from others is counted the $351 maximum, whatever the shelter is worth (3.520.79(C)(3)).

Mutation check. Each mutant fails both the property tests and the YAML:

• no ISM under the one-third reduction (reading c): 2 property and 8 YAML failures;
• $351 there (reading b): 2 and 8;
• dropping the couple halving: 1 and 2.

Tests

• YAML: the new co_ssa_in_kind_support_and_maintenance.yaml (18). co_state_supplement.yaml Case 28 now expects $240/yr instead of $3,976. Cases 33-37 are new (Apply Colorado's AND-CS payment floor and 3.549 income rules to every client #10161 owns 31-32). All 101 CO SSA cases pass.
• test_co_ism_invariants.py, measured locally on macOS under shared load: 7.5 s for the property test, 2.1 s for the worked examples, 1.41 GB peak RSS (nearly all of it model import). It runs in the Rest/core group.
• All Colorado YAML (gov/states/co, 705) and SSI YAML (gov/ssa/ssi, 229) pass on the rebased head, run locally with Python 3.13.
• test_co_ism_invariants.py, test_ssi_state_supplement_medicaid_dependency.py and test_ssi_state_supplement_couple_invariants.py pass. In test_co_and_cs_invariants.py (Apply Colorado's AND-CS payment floor and 3.549 income rules to every client #10161's), test_properties finds a married client with shelter support whose spouse's extra earnings change SSI's deeming status. The client's SSI rises from $7,952 to $11,198, and countable income falls $0.50/year. It fails identically on Apply Colorado's AND-CS payment floor and 3.549 income rules to every client #10161's head 87281e2751 and has been reported there.
• Partner fixtures (CO analytics coverage and My Friend Ben): 30 of 31 pass. co_state_supplement_disabled_ssi_couple_positive fails with the same value on Apply Colorado's AND-CS payment floor and 3.549 income rules to every client #10161's head. That is Pay CO, TX and NM SSI supplements to both members of an SSI couple #10145's change, already with @hua7450, so this PR changes no partner output.

Not modeled

• OAP: follows once Apply Colorado's OAP payment floor and count OAP income under 3.533-3.534 #10176 lands (one-line swap in co_oap_own_countable_income).
• 3.520.79(C)(1)-(2) by payment, fair share and market value: PE has no such inputs, so a client receiving shelter from others is counted the (C)(3) maximum.
• Life estates (D), and the pre-2014 educational-grant and boarder rules.
• Pre-2014 in-kind items other than food and shelter (clothing, etc.).
• The SSA-backlog good-cause exception.
• Pre-2014 OAP components: PE models OAP from 2023.
• ISM for 2002-2006: the 2004 table's base is unsettled (pre-2014 caveat).

Impact

No microsimulation change. Microcosm's concept coverage (docs/concept-coverage/policyengine-us.md, "Inputs no concept covers", as of 2026-10-12) lists all five SSI living-arrangement inputs (ssi_lives_in_another_persons_household, ssi_receives_shelter_from_others_in_household, ssi_receives_outside_shelter_support, ssi_others_pay_all_meals, ssi_shelter_support_value). The US frame leaves them false, so ISM is 0 for every record. Household calculations that set them change as above.

Axiom

axiom: TheAxiomFoundation/rulespec-us#1720 queued (3.520.79(B)(5)-(6), (C), client_ism_amount, 3.520.71(E); dispatch after d1446)

Review

GPT-6.1 Sol review, round 1 (9cb7d30b4b): REQUEST_CHANGES. One P2: Colorado's own amount was capped at the value of the shelter support, but 3.520.79(C) runs on the client's payment. Fixed in 0c4370a9d4. Round 1 confirmed the matching reading's arithmetic ($331.33 / $20; $248.50 / $258.50 for couples), found no dependency cycle, and confirmed the 2014 cap, food and matching dates.

Round 2 (0c4370a9d4): confirmed the P2 fix. It raised three P2s, fixed in 09e28190e9:

1. The no-backfill invariant ignored the $13 floor.
2. The 2004-2006 component base conflicts with the $513 table figure (the model now starts in 2007).
3. Hospital room and board is exempt (3.520.786(B)).

Round 2 accepted three items as documented: the 2002-03 carryback, now moot; the exemptions applying to pre-2014 food; and zero ISM for SSI recipients SSA doesn't charge. Its body corrections are applied: the PMV-couple amount, food independent of shelter, the qualified child statement, and timing and memory. Round 3: pending.

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