MaxGhenis · Nov 7, 2026 · Nov 9, 2026 · Nov 9, 2026
diff --git a/changelog.d/state-payroll-tax-history.fixed.md b/changelog.d/state-payroll-tax-history.fixed.md
@@ -0,0 +1 @@
+Give state employee payroll taxes their published 2018-2027 histories. Connecticut Paid Leave and the Oregon statewide transit tax no longer run back before contributions began (January 2021 and July 2018). Massachusetts PFML (from October 2019), New Jersey TDI and FLI, New York Paid Family Leave (from 2018) and Rhode Island TDI take each year's published rate and wage base for 2018-2023, where they read zero. Massachusetts PFML, the Oregon transit tax and the Vermont Child Care Contribution average the rates in force at the four quarter starts, so a partial first year counts only its months in force.
diff --git a/policyengine_us/parameters/gov/states/ct/tax/payroll/paid_leave/employee_rate.yaml b/policyengine_us/parameters/gov/states/ct/tax/payroll/paid_leave/employee_rate.yaml
@@ -1,5 +1,7 @@
 description: Employee-side Connecticut Paid Leave contribution rate.
 values:
+  # CGS 31-49g(b)(1) starts contributions on January 1, 2021.
+  0000-01-01: 0
   2021-01-01: 0.005
 
 metadata:

diff --git a/...gine_us/parameters/gov/states/ma/tax/payroll/paid_leave/employer_headcount_threshold.yaml b/...gine_us/parameters/gov/states/ma/tax/payroll/paid_leave/employer_headcount_threshold.yaml
@@ -1,7 +1,9 @@
 description: Minimum employer size for Massachusetts PFML employer contributions.
 values:
   0000-01-01: 0
-  2024-01-01: 25
+  # Contributions began October 1, 2019, after legislation delayed the start by
+  # three months from July 1, 2019.
+  2019-10-01: 25
 
 metadata:
   period: year
@@ -12,6 +14,16 @@ metadata:
       href: https://malegislature.gov/Laws/GeneralLaws/PartI/TitleXXII/Chapter175M/Section6
     - title: Massachusetts Paid Family and Medical Leave employer contribution rates and calculator
       href: https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
+    - title: Massachusetts Department of Family and Medical Leave, Notice to Massachusetts employers about the PFML delay (June 14, 2019; archived July 16, 2019)
+      href: https://web.archive.org/web/20190716144139/https://www.mass.gov/news/notice-to-massachusetts-employers-about-pfml-delay
+    - title: Massachusetts Paid Family and Medical Leave contribution rates for employers, 2019 (archived November 19, 2019)
+      href: https://web.archive.org/web/20191119050248/https://www.mass.gov/info-details/family-and-medical-leave-contribution-rates-for-employers
+    - title: Massachusetts Paid Family and Medical Leave contribution rates for employers, 2020 (archived July 15, 2020)
+      href: https://web.archive.org/web/20200715141908/https://www.mass.gov/info-details/family-and-medical-leave-contribution-rates-for-employers
+    - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2021 and 2022 sections (archived December 24, 2021)
+      href: https://web.archive.org/web/20211224090330/https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
+    - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2022 and 2023 sections (archived March 16, 2023)
+      href: https://web.archive.org/web/20230316153652/https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
     - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2024 section (archived May 26, 2024)
       href: https://web.archive.org/web/20240526092717/https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
     - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2025 & 2026 section (archived December 8, 2025)

diff --git a/policyengine_us/parameters/gov/states/ma/tax/payroll/paid_leave/family_employee_share.yaml b/policyengine_us/parameters/gov/states/ma/tax/payroll/paid_leave/family_employee_share.yaml
@@ -1,7 +1,10 @@
 description: Massachusetts limits an employer's deduction from wages to this share of the family leave contribution under the Paid Family and Medical Leave program.
 values:
   0000-01-01: 0
-  2024-01-01: 1
+  # Contributions began October 1, 2019, after legislation delayed the start by
+  # three months from July 1, 2019. From the start the employer could withhold
+  # the whole family leave contribution.
+  2019-10-01: 1
   # Acts 2026 c. 101 s. 26 strikes "100" in s. 6(c)(2), (d) and (e)(2) and inserts "40".
   # Dated 2027-01-01 to match the rates the Department of Family and Medical Leave published. Section 45 applies ss. 25-26 to taxable years from 2026, and s. 43(a) directs guidance for calendar year 2027.
   2027-01-01: 0.4
@@ -15,6 +18,16 @@ metadata:
       href: https://malegislature.gov/Laws/GeneralLaws/PartI/TitleXXII/Chapter175M/Section6
     - title: Massachusetts Paid Family and Medical Leave employer contribution rates and calculator (2026 and 2027 sections, updated October 1, 2026)
       href: https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
+    - title: Massachusetts Department of Family and Medical Leave, Notice to Massachusetts employers about the PFML delay (June 14, 2019; archived July 16, 2019)
+      href: https://web.archive.org/web/20190716144139/https://www.mass.gov/news/notice-to-massachusetts-employers-about-pfml-delay
+    - title: Massachusetts Paid Family and Medical Leave contribution rates for employers, 2019 (archived November 19, 2019)
+      href: https://web.archive.org/web/20191119050248/https://www.mass.gov/info-details/family-and-medical-leave-contribution-rates-for-employers
+    - title: Massachusetts Paid Family and Medical Leave contribution rates for employers, 2020 (archived July 15, 2020)
+      href: https://web.archive.org/web/20200715141908/https://www.mass.gov/info-details/family-and-medical-leave-contribution-rates-for-employers
+    - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2021 and 2022 sections (archived December 24, 2021)
+      href: https://web.archive.org/web/20211224090330/https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
+    - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2022 and 2023 sections (archived March 16, 2023)
+      href: https://web.archive.org/web/20230316153652/https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
     - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2024 section (archived May 26, 2024)
       href: https://web.archive.org/web/20240526092717/https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
     - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2025 & 2026 section (archived December 8, 2025)

diff --git a/policyengine_us/parameters/gov/states/ma/tax/payroll/paid_leave/family_rate.yaml b/policyengine_us/parameters/gov/states/ma/tax/payroll/paid_leave/family_rate.yaml
@@ -1,6 +1,11 @@
 description: Massachusetts PFML family leave contribution rate.
 values:
   0000-01-01: 0
+  # Contributions began October 1, 2019, after legislation delayed the start by
+  # three months from July 1, 2019.
+  2019-10-01: 0.0013
+  2022-01-01: 0.0012
+  2023-01-01: 0.0011
   2024-01-01: 0.0018
   # DFML's 2027 rates swap with the deduction caps (Acts 2026 c. 101 s. 43(a)), leaving the employee and employer totals unchanged.
   2027-01-01: 0.007
@@ -14,6 +19,16 @@ metadata:
       href: https://malegislature.gov/Laws/GeneralLaws/PartI/TitleXXII/Chapter175M/Section6
     - title: Massachusetts Paid Family and Medical Leave employer contribution rates and calculator (2026 and 2027 sections, updated October 1, 2026)
       href: https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
+    - title: Massachusetts Department of Family and Medical Leave, Notice to Massachusetts employers about the PFML delay (June 14, 2019; archived July 16, 2019)
+      href: https://web.archive.org/web/20190716144139/https://www.mass.gov/news/notice-to-massachusetts-employers-about-pfml-delay
+    - title: Massachusetts Paid Family and Medical Leave contribution rates for employers, 2019 (archived November 19, 2019)
+      href: https://web.archive.org/web/20191119050248/https://www.mass.gov/info-details/family-and-medical-leave-contribution-rates-for-employers
+    - title: Massachusetts Paid Family and Medical Leave contribution rates for employers, 2020 (archived July 15, 2020)
+      href: https://web.archive.org/web/20200715141908/https://www.mass.gov/info-details/family-and-medical-leave-contribution-rates-for-employers
+    - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2021 and 2022 sections (archived December 24, 2021)
+      href: https://web.archive.org/web/20211224090330/https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
+    - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2022 and 2023 sections (archived March 16, 2023)
+      href: https://web.archive.org/web/20230316153652/https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
     - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2024 section (archived May 26, 2024)
       href: https://web.archive.org/web/20240526092717/https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
     - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2025 & 2026 section (archived December 8, 2025)

diff --git a/policyengine_us/parameters/gov/states/ma/tax/payroll/paid_leave/medical_employee_share.yaml b/policyengine_us/parameters/gov/states/ma/tax/payroll/paid_leave/medical_employee_share.yaml
@@ -1,7 +1,9 @@
 description: Massachusetts limits an employer's deduction from wages to this share of the medical leave contribution under the Paid Family and Medical Leave program.
 values:
   0000-01-01: 0
-  2024-01-01: 0.4
+  # Contributions began October 1, 2019, after legislation delayed the start by
+  # three months from July 1, 2019.
+  2019-10-01: 0.4
   # Acts 2026 c. 101 s. 25 strikes "40" in s. 6(c)(1), (d) and (e)(1) and inserts "100".
   # Dated 2027-01-01 to match the rates the Department of Family and Medical Leave published. Section 45 applies ss. 25-26 to taxable years from 2026, and s. 43(a) directs guidance for calendar year 2027.
   2027-01-01: 1
@@ -15,6 +17,16 @@ metadata:
       href: https://malegislature.gov/Laws/GeneralLaws/PartI/TitleXXII/Chapter175M/Section6
     - title: Massachusetts Paid Family and Medical Leave employer contribution rates and calculator (2026 and 2027 sections, updated October 1, 2026)
       href: https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
+    - title: Massachusetts Department of Family and Medical Leave, Notice to Massachusetts employers about the PFML delay (June 14, 2019; archived July 16, 2019)
+      href: https://web.archive.org/web/20190716144139/https://www.mass.gov/news/notice-to-massachusetts-employers-about-pfml-delay
+    - title: Massachusetts Paid Family and Medical Leave contribution rates for employers, 2019 (archived November 19, 2019)
+      href: https://web.archive.org/web/20191119050248/https://www.mass.gov/info-details/family-and-medical-leave-contribution-rates-for-employers
+    - title: Massachusetts Paid Family and Medical Leave contribution rates for employers, 2020 (archived July 15, 2020)
+      href: https://web.archive.org/web/20200715141908/https://www.mass.gov/info-details/family-and-medical-leave-contribution-rates-for-employers
+    - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2021 and 2022 sections (archived December 24, 2021)
+      href: https://web.archive.org/web/20211224090330/https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
+    - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2022 and 2023 sections (archived March 16, 2023)
+      href: https://web.archive.org/web/20230316153652/https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
     - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2024 section (archived May 26, 2024)
       href: https://web.archive.org/web/20240526092717/https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
     - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2025 & 2026 section (archived December 8, 2025)

diff --git a/policyengine_us/parameters/gov/states/ma/tax/payroll/paid_leave/medical_rate.yaml b/policyengine_us/parameters/gov/states/ma/tax/payroll/paid_leave/medical_rate.yaml
@@ -1,6 +1,11 @@
 description: Massachusetts PFML medical leave contribution rate.
 values:
   0000-01-01: 0
+  # Contributions began October 1, 2019, after legislation delayed the start by
+  # three months from July 1, 2019.
+  2019-10-01: 0.0062
+  2022-01-01: 0.0056
+  2023-01-01: 0.0052
   2024-01-01: 0.007
   # DFML's 2027 rates swap with the deduction caps (Acts 2026 c. 101 s. 43(a)), leaving the employee and employer totals unchanged.
   2027-01-01: 0.0018
@@ -14,6 +19,16 @@ metadata:
       href: https://malegislature.gov/Laws/GeneralLaws/PartI/TitleXXII/Chapter175M/Section6
     - title: Massachusetts Paid Family and Medical Leave employer contribution rates and calculator (2026 and 2027 sections, updated October 1, 2026)
       href: https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
+    - title: Massachusetts Department of Family and Medical Leave, Notice to Massachusetts employers about the PFML delay (June 14, 2019; archived July 16, 2019)
+      href: https://web.archive.org/web/20190716144139/https://www.mass.gov/news/notice-to-massachusetts-employers-about-pfml-delay
+    - title: Massachusetts Paid Family and Medical Leave contribution rates for employers, 2019 (archived November 19, 2019)
+      href: https://web.archive.org/web/20191119050248/https://www.mass.gov/info-details/family-and-medical-leave-contribution-rates-for-employers
+    - title: Massachusetts Paid Family and Medical Leave contribution rates for employers, 2020 (archived July 15, 2020)
+      href: https://web.archive.org/web/20200715141908/https://www.mass.gov/info-details/family-and-medical-leave-contribution-rates-for-employers
+    - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2021 and 2022 sections (archived December 24, 2021)
+      href: https://web.archive.org/web/20211224090330/https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
+    - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2022 and 2023 sections (archived March 16, 2023)
+      href: https://web.archive.org/web/20230316153652/https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
     - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2024 section (archived May 26, 2024)
       href: https://web.archive.org/web/20240526092717/https://www.mass.gov/info-details/paid-family-and-medical-leave-employer-contribution-rates-and-calculator
     - title: Massachusetts Paid Family and Medical Leave employer contribution rates, 2025 & 2026 section (archived December 8, 2025)

diff --git a/...yengine_us/parameters/gov/states/nj/tax/payroll/family_leave_insurance/employee_rate.yaml b/...yengine_us/parameters/gov/states/nj/tax/payroll/family_leave_insurance/employee_rate.yaml
@@ -1,9 +1,17 @@
 description: Employee-side New Jersey family leave insurance contribution rate.
 values:
-  0000-01-01: 0
+  # Worker FLI contributions existed before 2018. The model does not encode earlier
+  # years, so it carries the 2018 value back to 2015, its first year.
+  2018-01-01: 0.0009
+  2019-01-01: 0.0008
+  2020-01-01: 0.0016
+  2021-01-01: 0.0028
+  2022-01-01: 0.0014
+  2023-01-01: 0.0006
   2024-01-01: 0.0009
   2025-01-01: 0.0033
   2026-01-01: 0.0023
+  2027-01-01: 0.0024
 
 metadata:
   period: year

diff --git a/...us/parameters/gov/states/nj/tax/payroll/temporary_disability_insurance/employee_rate.yaml b/...us/parameters/gov/states/nj/tax/payroll/temporary_disability_insurance/employee_rate.yaml
@@ -1,9 +1,17 @@
 description: Employee-side New Jersey temporary disability insurance contribution rate.
 values:
-  0000-01-01: 0
+  # Worker TDI contributions existed before 2018. The model does not encode earlier
+  # years, so it carries the 2018 value back to 2015, its first year.
+  2018-01-01: 0.0019
+  2019-01-01: 0.0017
+  2020-01-01: 0.0026
+  2021-01-01: 0.0047
+  2022-01-01: 0.0014
+  2023-01-01: 0
   2024-01-01: 0
   2025-01-01: 0.0023
   2026-01-01: 0.0019
+  2027-01-01: 0.0024
 
 metadata:
   period: year

diff --git a/...arameters/gov/states/nj/tax/payroll/temporary_disability_insurance/taxable_wage_base.yaml b/...arameters/gov/states/nj/tax/payroll/temporary_disability_insurance/taxable_wage_base.yaml
@@ -1,6 +1,15 @@
 description: Taxable wage base for New Jersey TDI and FLI employee contributions.
 values:
-  0000-01-01: 0
+  # The worker TDI and FLI wage base existed before 2018. The model does not encode
+  # earlier years, so it carries the 2018 value back to 2015, its first year.
+  # NJDOL lists one wage base for UI, TDI and FLI through 2019. From 2020 the
+  # worker TDI and FLI base is separate.
+  2018-01-01: 33_700
+  2019-01-01: 34_400
+  2020-01-01: 134_900
+  2021-01-01: 138_200
+  2022-01-01: 151_900
+  2023-01-01: 156_800
   2024-01-01: 161_400
   2025-01-01: 165_400
   2026-01-01: 171_100

diff --git a/...ne_us/parameters/gov/states/ny/tax/payroll/paid_family_leave/annual_max_contribution.yaml b/...ne_us/parameters/gov/states/ny/tax/payroll/paid_family_leave/annual_max_contribution.yaml
@@ -1,6 +1,13 @@
 description: Maximum annual New York Paid Family Leave employee contribution.
 values:
+  # Contributions began January 1, 2018.
   0000-01-01: 0
+  2018-01-01: 85.56
+  2019-01-01: 107.97
+  2020-01-01: 196.72
+  2021-01-01: 385.34
+  2022-01-01: 423.71
+  2023-01-01: 399.43
   2024-01-01: 333.25
   2025-01-01: 354.53
   2026-01-01: 411.91
@@ -13,6 +20,20 @@ metadata:
   reference:
     - title: New York Workers' Compensation Law Section 209
       href: https://www.nysenate.gov/legislation/laws/WKC/209
+    - title: New York Department of Financial Services, Decision on premium rate for Paid Family Leave benefits and maximum employee contribution for coverage beginning January 1, 2018
+      href: https://www.dfs.ny.gov/apps_and_licensing/health_insurers/pfl_rate_decision_2018_page
+    - title: New York State Office of the State Comptroller, Payroll Bulletin 1619, New York State Paid Family Leave Program (2018 maximum annual deduction of $85.56)
+      href: https://www.osc.ny.gov/state-agencies/payroll-bulletins/state-agencies/1619-new-york-state-paid-family-leave-program-ny-paid-family-leave
+    - title: New York Department of Financial Services, Decision on premium rate for Paid Family Leave benefits and maximum employee contribution for coverage beginning January 1, 2019
+      href: https://www.dfs.ny.gov/apps_and_licensing/health_insurers/pfl_rate_decision_2019_page
+    - title: New York Department of Financial Services, Decision on premium rate for Paid Family Leave benefits and maximum employee contribution for coverage beginning January 1, 2020
+      href: https://www.dfs.ny.gov/apps_and_licensing/health_insurers/pfl_rate_decision_2020_page
+    - title: New York Department of Financial Services, Decision on premium rate for Paid Family Leave benefits and maximum employee contribution for coverage beginning January 1, 2021
+      href: https://www.dfs.ny.gov/apps_and_licensing/health_insurers/pfl_rate_decision_2021_page
+    - title: New York Department of Financial Services, Decision on premium rate for Paid Family Leave benefits and maximum employee contribution for coverage beginning January 1, 2022
+      href: https://www.dfs.ny.gov/apps_and_licensing/health_insurers/pfl_rate_decision_2022
+    - title: New York Department of Financial Services, Decision on premium rate for Paid Family Leave benefits and maximum employee contribution for coverage beginning January 1, 2023
+      href: https://www.dfs.ny.gov/apps_and_licensing/health_insurers/pfl_rate_decision_2023
     - title: New York Workers' Compensation Board, NYS Paid Family Leave enhancements for 2024 (January 5, 2024)
       href: https://www.wcb.ny.gov/content/main/PressRe/pfl-enhancements-2024.jsp
     - title: New York Department of Financial Services, Decision on premium rate for Paid Family Leave benefits and maximum employee contribution for coverage beginning January 1, 2025
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		Give state employee payroll taxes their published 2018-2027 histories. Connecticut Paid Leave and the Oregon statewide transit tax no longer run back before contributions began (January 2021 and July 2018). Massachusetts PFML (from October 2019), New Jersey TDI and FLI, New York Paid Family Leave (from 2018) and Rhode Island TDI take each year's published rate and wage base for 2018-2023, where they read zero. Massachusetts PFML, the Oregon transit tax and the Vermont Child Care Contribution average the rates in force at the four quarter starts, so a partial first year counts only its months in force.