TAXSIM EITC age limits for childless filers: off-by-one and missing ARPA 2021 expansion? #714
Description
Summary
When comparing PolicyEngine and TAXSIM results for 2021 CPS data, we noticed discrepancies in the Earned Income Tax Credit for childless filers age 65+. TAXSIM appears to cap childless EITC eligibility at age 65 for 2021, but ARPA (IRC 32(n)) removed the upper age limit for that year. There also appears to be an off-by-one in the pre-ARPA upper bound (age 65 included vs. age 64 per statute).
What the law says
Pre-ARPA — IRC 32(c)(1)(A)(ii)(II):
"such individual ... has attained age 25 but not attained age 65 before the close of the taxable year"
Eligible ages: 25–64.
ARPA 2021 — IRC 32(n)(1)(B):
"Subsection (c)(1)(A)(ii)(II) shall be applied without regard to the phrase 'but not attained age 65'"
Eligible ages for 2021: 19+ with no upper limit. This was temporary (2021 only).
What TAXSIM produces
We ran controlled test cases (single, childless, $10,000 wages, idtl=2) and observed:
| Year | Age 64 | Age 65 | Age 66 | Expected (per IRC 32) |
|---|---|---|---|---|
| 2020 | $445 EITC | $445 EITC | $0 | 65 should be $0 |
| 2021 | $1,502 EITC | $1,502 EITC | $0 | 66 should be $1,502 |
| 2022 | $496 EITC | $496 EITC | $0 | 65 should be $0 |
Two potential issues:
-
2021 (ARPA): EITC drops to $0 at age 66, but IRC 32(n) removed the upper age limit entirely for 2021. Filers age 66+ should be eligible.
-
2020/2022+ (pre-ARPA): EITC is given at age 65, but the statute says "not attained age 65" — meaning age 64 is the last eligible age.
Where we think this originates
In eicage.for, the age check uses in(age, 19, 65) for 2021 (and in(age, 25, 65) for other years). The in() function is inclusive on both bounds. For 2021, the upper bound of 65 should be removed per ARPA. For other years, the upper bound should be 64 rather than 65 to match "not attained age 65."
We also noticed the comment at eitcr.for line 211–213 acknowledges the ARPA change ("2021: you no longer need to be under age 65 to claim the EIC w/o a qualifying [child]"), but the code at line 229 still uses in(age, 19, 65).
Impact
In our 1000-record CPS comparison, 8 records are affected — all childless filers age 66+ with Social Security income. TAXSIM gives $0 EITC; we believe they should receive $417–$1,382 each under the 2021 ARPA rules.
Are we reading the statute correctly, or is there a reason TAXSIM intentionally caps at 65 for 2021?