MaxGhenis · Sep 26, 2026 · Sep 25, 2026 · Sep 25, 2026 · Sep 25, 2026 · Sep 25, 2026
diff --git a/changelog.d/fix-ar-2015-2020-parameter-history.fixed.md b/changelog.d/fix-ar-2015-2020-parameter-history.fixed.md
@@ -0,0 +1 @@
+Arkansas 2015-2020 income tax parameters no longer fall back on 2021-2022 values: add each year's low income tax tables, personal tax credit amount ($26 through 2019), and tuition deduction caps; exempt unemployment compensation through 2017; before 2018, make military retirement share the $6,000 retirement exemption and block the 65 Special credit for filers who claim it; and zero the 2022 credits before they existed.
diff --git a/...tes/ar/tax/income/credits/additional_tax_credit_for_qualified_individuals/max_amount.yaml b/...tes/ar/tax/income/credits/additional_tax_credit_for_qualified_individuals/max_amount.yaml
@@ -4,6 +4,8 @@ metadata:
   unit: currency-USD
   label: Arkansas additional tax credit for qualified individuals max amount
   reference:
+    - title: Arkansas 2022 Individual Income Tax Instructions, Special Information for Tax Year 2022 (new credits)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/2022_AR1000F_and_AR1000NR_Instructions.pdf#page=6
     - title: Arkansas 2023 Additional Tax Credit for Qualified Individuals Worksheet
       href: https://www.dfa.arkansas.gov/wp-content/uploads/2023_Final_AdditionalTaxCreditforQualifiedIndividuals_FI.pdf
     - title: Arkansas 2022 Additional Tax Credit for Qualified Individuals Worksheet
@@ -14,4 +16,6 @@ metadata:
       href: https://law.justia.com/codes/arkansas/title-26/subtitle-5/chapter-51/subchapter-5/section-26-51-501/
 
 values:
+  # Created for tax year 2022 by Act 1 of the Second Extraordinary Session of 2021.
+  2015-01-01: 0
   2022-01-01: 60
diff --git a/...engine_us/parameters/gov/states/ar/tax/income/credits/inflationary_relief/max_amount.yaml b/...engine_us/parameters/gov/states/ar/tax/income/credits/inflationary_relief/max_amount.yaml
@@ -5,6 +5,8 @@ metadata:
   unit: currency-USD
   label: Arkansas inflation relief credit maximum amount
   reference:
+    - title: Arkansas 2022 Individual Income Tax Instructions, Special Information for Tax Year 2022 (new credits)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/2022_AR1000F_and_AR1000NR_Instructions.pdf#page=6
     # The inflation relief credit is not mentioned in the Arkansas statutes
     - title: Arkansas 2022 Individual Income Tax Forms and Instructions
       href: https://www.dfa.arkansas.gov/wp-content/uploads/2022_AR1000F_and_AR1000NR_Instructions.pdf#page=25
@@ -17,22 +19,27 @@ metadata:
   breakdown:
     - filing_status
 JOINT:
+  2015-01-01: 0
   2022-01-01: 300
   2023-01-01: 300
   2024-01-01: 0
 SURVIVING_SPOUSE:
+  2015-01-01: 0
   2022-01-01: 150
   2023-01-01: 150
   2024-01-01: 0
 HEAD_OF_HOUSEHOLD:
+  2015-01-01: 0
   2022-01-01: 150
   2023-01-01: 150
   2024-01-01: 0
 SINGLE:
+  2015-01-01: 0
   2022-01-01: 150
   2023-01-01: 150
   2024-01-01: 0
 SEPARATE:
+  2015-01-01: 0
   2022-01-01: 150
   2023-01-01: 150
   2024-01-01: 0
diff --git a/policyengine_us/parameters/gov/states/ar/tax/income/credits/personal/age_threshold.yaml b/policyengine_us/parameters/gov/states/ar/tax/income/credits/personal/age_threshold.yaml
@@ -3,7 +3,7 @@ values:
   2021-01-01: 65
 
 metadata:
-  unit: currency-USD
+  unit: year
   period: year
   label: Arkansas aged personal credit age threshold
   reference:

diff --git a/policyengine_us/parameters/gov/states/ar/tax/income/credits/personal/amount/base.yaml b/policyengine_us/parameters/gov/states/ar/tax/income/credits/personal/amount/base.yaml
@@ -1,12 +1,27 @@
 description: Arkansas provides this base personal tax credit amount.
 values:
-  2021-01-01: 29
+  2014-01-01: 26
+  2020-01-01: 29
 
 metadata:
   unit: currency-USD
   period: year
   label: Arkansas personal tax credit base amount
   reference:
+    - title: Arkansas 2014 Individual Income Tax Instructions, Lines 7A and 7B
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/LongBookwTaxTables_2014.pdf#page=13
+    - title: Arkansas 2015 Individual Income Tax Instructions, Lines 7A and 7B
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/LongBookwTaxTables_2015.pdf#page=13
+    - title: Arkansas 2016 Individual Income Tax Instructions, Lines 7A and 7B
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/LongBookwTaxTables_2016.pdf#page=11
+    - title: Arkansas 2017 Individual Income Tax Instructions, Lines 7A and 7B
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1000FandAR1000NRInstructions.pdf#page=11
+    - title: Arkansas 2018 Individual Income Tax Instructions, Lines 7A and 7B
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1000FandAR1000NRInstructions_2018.pdf#page=11
+    - title: Arkansas 2019 Individual Income Tax Instructions, Lines 7A and 7B
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/2019_AR1000F_and_AR1000NR_Instructions.pdf#page=11
+    - title: Arkansas 2020 Individual Income Tax Instructions, Lines 7A and 7B
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/2020_AR1000F_and_AR1000NR_Instructions.pdf#page=11
     - title: Arkansas 2022 Individual Income Tax Forms and Instructions, LINE 7A.
       href: https://www.dfa.arkansas.gov/wp-content/uploads/2022_AR1000F_and_AR1000NR_Instructions.pdf#page=12
     - title: 2022 AR1000F ARKANSAS INDIVIDUAL INCOME TAX RETURN Full Year Resident

diff --git a/...ar/tax/income/deductions/itemized/tuition/weighted_average_tuition/four_year_college.yaml b/...ar/tax/income/deductions/itemized/tuition/weighted_average_tuition/four_year_college.yaml
@@ -1,5 +1,11 @@
 description: Arkansas defines the weighted average tuition for four-year colleges at this amount under the post secondary education tuition deduction.
 values:
+  2015-01-01: 3_936
+  2016-01-01: 4_118
+  2017-01-01: 4_282
+  2018-01-01: 4_370
+  2019-01-01: 4_503
+  2020-01-01: 4_531
   2021-01-01: 4_602
   2022-01-01: 4_712
   2023-01-01: 4_819
@@ -12,6 +18,18 @@ metadata:
   uprating: gov.irs.uprating
   label: Arkansas post secondary eduction tuition deduction four-year college weighted average tuition
   reference:
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2015)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075_2015_RE.pdf#page=1
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2016)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075_2016_RE.pdf#page=1
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2017)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075DedforTuitionPaidtoPostSecEduInst.pdf#page=1
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2018)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/2018_Final_AR1075_BC_FI.pdf#page=1
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2019)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075_2019.pdf#page=1
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2020)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075_2020.pdf#page=1
     - title: Arkansas Individual Income Tax Return Deduction for Tution Paid to Post-Secondary Educational Institutions AR1075 Rev.2022
       href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075_2022.pdf#page=1
     - title: Arkansas Individual Income Tax Return Deduction for Tution Paid to Post-Secondary Educational Institutions AR1075 Rev.2021

diff --git a/...tax/income/deductions/itemized/tuition/weighted_average_tuition/technical_institutes.yaml b/...tax/income/deductions/itemized/tuition/weighted_average_tuition/technical_institutes.yaml
@@ -1,5 +1,11 @@
 description: Arkansas defines the weighted average tuition for technical institutes at this amount under the post secondary education tuition deduction.
 values:
+  2015-01-01: 592
+  2016-01-01: 560
+  2017-01-01: 711
+  2018-01-01: 772
+  2019-01-01: 778
+  2020-01-01: 800
   2021-01-01: 780
   2024-01-01: 1_515
 
@@ -8,6 +14,18 @@ metadata:
   unit: currency-USD
   label: Arkansas post secondary eduction tuition deduction technical institutes weighted average tuition 
   reference:
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2015)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075_2015_RE.pdf#page=1
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2016)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075_2016_RE.pdf#page=1
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2017)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075DedforTuitionPaidtoPostSecEduInst.pdf#page=1
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2018)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/2018_Final_AR1075_BC_FI.pdf#page=1
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2019)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075_2019.pdf#page=1
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2020)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075_2020.pdf#page=1
     - title: Arkansas Individual Income Tax Return Deduction for Tution Paid to Post-Secondary Educational Institutions AR1075 Rev.2022
       href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075_2022.pdf#page=1
     - title: Arkansas Individual Income Tax Return Deduction for Tution Paid to Post-Secondary Educational Institutions AR1075 Rev.2021

diff --git a/.../ar/tax/income/deductions/itemized/tuition/weighted_average_tuition/two_year_college.yaml b/.../ar/tax/income/deductions/itemized/tuition/weighted_average_tuition/two_year_college.yaml
@@ -1,5 +1,11 @@
 description: Arkansas defines the weighted average tuition for four-year colleges at this amount under the post secondary education tuition deduction.
 values:
+  2015-01-01: 1_884
+  2016-01-01: 1_965
+  2017-01-01: 2_024
+  2018-01-01: 2_055
+  2019-01-01: 2_114
+  2020-01-01: 2_127
   2021-01-01: 2_141
   2022-01-01: 2_272
   2023-01-01: 2_405
@@ -11,6 +17,18 @@ metadata:
   uprating: gov.irs.uprating
   label: Arkansas post secondary eduction tuition deduction two-year college weighted average tuition
   reference:
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2015)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075_2015_RE.pdf#page=1
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2016)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075_2016_RE.pdf#page=1
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2017)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075DedforTuitionPaidtoPostSecEduInst.pdf#page=1
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2018)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/2018_Final_AR1075_BC_FI.pdf#page=1
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2019)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075_2019.pdf#page=1
+    - title: Arkansas Deduction for Tuition Paid to Post-Secondary Educational Institutions, AR1075 (2020)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075_2020.pdf#page=1
     - title: Arkansas Individual Income Tax Return Deduction for Tution Paid to Post-Secondary Educational Institutions AR1075 Rev.2022
       href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1075_2022.pdf#page=1
     - title: Arkansas Individual Income Tax Return Deduction for Tution Paid to Post-Secondary Educational Institutions AR1075 Rev.2021

diff --git a/...income/exemptions/retirement_or_disability_benefits/military_retirement_fully_exempt.yaml b/...income/exemptions/retirement_or_disability_benefits/military_retirement_fully_exempt.yaml
@@ -0,0 +1,16 @@
+description: Arkansas fully exempts military retirement pay from income tax if this is true; otherwise military retirement shares the retirement benefits exemption cap with employment-related pensions and IRA distributions.
+values:
+  2015-01-01: false
+  # Act 141 of 2017 exempts military retirement from tax year 2018.
+  2018-01-01: true
+metadata:
+  unit: bool
+  period: year
+  label: Arkansas military retirement full exemption in effect
+  reference:
+    - title: Arkansas 2016 Individual Income Tax Instructions, Line 9A (enter U.S. military retirement on Line 17A) and Line 17A ($6,000 exemption)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/LongBookwTaxTables_2016.pdf#page=12
+    - title: Arkansas 2017 Individual Income Tax Instructions, Additional Information for Tax Year 2018 (Military Retirement Exemption, Act 141 of 2017)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1000FandAR1000NRInstructions.pdf#page=5
+    - title: Arkansas Act 141 of 2017
+      href: https://www.arkleg.state.ar.us/Acts/FTPDocument?path=%2FACTS%2F2017R%2FPublic%2F&file=141.pdf&ddBienniumSession=2017%2F2017R
diff --git a/policyengine_us/parameters/gov/states/ar/tax/income/gross_income/sources/individual.yaml b/policyengine_us/parameters/gov/states/ar/tax/income/gross_income/sources/individual.yaml
@@ -1,5 +1,21 @@
 description: Arkansas accounts for these sources when calculating the gross income.
 values:
+  # Unemployment compensation was exempt income through tax year 2017.
+  2015-01-01:
+    - irs_employment_income # Line 8
+    - self_employment_income # Line 8
+    - sstb_self_employment_income
+    - interest_income # Line 10
+    - dividend_income # Line 11
+    - alimony_income # Line 12
+    - ar_taxable_capital_gains_indiv # Line 13
+    - taxable_ira_distributions # Line 16
+    - taxable_roth_conversions # Line 16
+    - military_retirement_pay # Line 17
+    - taxable_pension_income # Line 18
+    - disability_benefits # Line 18b
+    - rental_income # Line 19
+    - farm_rent_income # Line 20
   # Act 141 of 2017 added unemployment compensation to gross income for tax
   # years beginning on or after January 1, 2018. Act 154 of 2021 then exempted
   # it for calendar years 2020 and 2021, after which it is taxable again.
@@ -60,6 +76,14 @@ metadata:
   period: year
   label: Arkansas gross income sources when married filing separately
   reference:
+    - title: Arkansas 2015 Individual Income Tax Instructions (unemployment compensation is exempt from tax)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/LongBookwTaxTables_2015.pdf#page=12
+    - title: Arkansas 2016 Individual Income Tax Instructions (unemployment compensation is exempt from tax)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/LongBookwTaxTables_2016.pdf#page=10
+    - title: Arkansas 2017 Individual Income Tax Instructions (unemployment compensation is exempt from tax)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1000FandAR1000NRInstructions.pdf#page=10
+    - title: Arkansas 2017 Individual Income Tax Instructions (Act 141 of 2017 makes unemployment compensation taxable from tax year 2018)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1000FandAR1000NRInstructions.pdf#page=5
     - title: Arkansas 2025 Individual Income Tax Forms and Instructions
       href: https://www.dfa.arkansas.gov/wp-content/uploads/2025_AR1000F_and_AR1000NR_Instructions.pdf#page=13
     - title: Arkansas 2022 AR1000F Instructions

diff --git a/policyengine_us/parameters/gov/states/ar/tax/income/gross_income/sources/joint.yaml b/policyengine_us/parameters/gov/states/ar/tax/income/gross_income/sources/joint.yaml
@@ -1,5 +1,21 @@
 description: Arkansas accounts for these sources when calculating the gross income.
 values:
+  # Unemployment compensation was exempt income through tax year 2017.
+  2015-01-01:
+    - irs_employment_income # Line 8
+    - self_employment_income # Line 8
+    - sstb_self_employment_income
+    - interest_income # Line 10
+    - dividend_income # Line 11
+    - alimony_income # Line 12
+    - ar_taxable_capital_gains_joint # Line 13
+    - taxable_ira_distributions # Line 16
+    - taxable_roth_conversions # Line 16
+    - military_retirement_pay # Line 17
+    - taxable_pension_income # Line 18
+    - disability_benefits # Line 18b
+    - rental_income # Line 19
+    - farm_rent_income # Line 20
   # Act 141 of 2017 added unemployment compensation to gross income for tax
   # years beginning on or after January 1, 2018. Act 154 of 2021 then exempted
   # it for calendar years 2020 and 2021, after which it is taxable again.
@@ -60,6 +76,14 @@ metadata:
   period: year
   label: Arkansas gross income sources when married filing jointly
   reference:
+    - title: Arkansas 2015 Individual Income Tax Instructions (unemployment compensation is exempt from tax)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/LongBookwTaxTables_2015.pdf#page=12
+    - title: Arkansas 2016 Individual Income Tax Instructions (unemployment compensation is exempt from tax)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/LongBookwTaxTables_2016.pdf#page=10
+    - title: Arkansas 2017 Individual Income Tax Instructions (unemployment compensation is exempt from tax)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1000FandAR1000NRInstructions.pdf#page=10
+    - title: Arkansas 2017 Individual Income Tax Instructions (Act 141 of 2017 makes unemployment compensation taxable from tax year 2018)
+      href: https://www.dfa.arkansas.gov/wp-content/uploads/AR1000FandAR1000NRInstructions.pdf#page=5
     - title: Arkansas 2025 Individual Income Tax Forms and Instructions
       href: https://www.dfa.arkansas.gov/wp-content/uploads/2025_AR1000F_and_AR1000NR_Instructions.pdf#page=13
     - title: Arkansas 2022 AR1000F Instructions
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Arkansas 2015-2020 income tax parameters no longer fall back on 2021-2022 values: add each year's low income tax tables, personal tax credit amount ($26 through 2019), and tuition deduction caps; exempt unemployment compensation through 2017; before 2018, make military retirement share the $6,000 retirement exemption and block the 65 Special credit for filers who claim it; and zero the 2022 credits before they existed.