From 29f91fc3b133980a376f8e6d21cbcd9f2169f485 Mon Sep 17 00:00:00 2001
From: duncanhobbs <duncan2012@gmail.com>
Date: Wed, 29 Sep 2021 14:06:55 -0400
Subject: [PATCH 01/22] Divide CDCC_crt and CDCC_frt parameters by 100 to match
 other parameters.

---
 taxcalc/calcfunctions.py        |  2 +-
 taxcalc/policy_current_law.json | 14 +++++++-------
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/taxcalc/calcfunctions.py b/taxcalc/calcfunctions.py
index b4dd79d23..d4df6f8f7 100644
--- a/taxcalc/calcfunctions.py
+++ b/taxcalc/calcfunctions.py
@@ -2159,7 +2159,7 @@ def F2441(MARS, earned_p, earned_s, f2441, CDCC_c, e32800,
         if c00100 > CDCC_ps2:
             crate = max(0., CDCC_frt -
                         max(((c00100 - CDCC_ps2) * CDCC_prt), 0.))
-    c33200 = c33000 * 0.01 * crate
+    c33200 = c33000 * crate
     # credit is limited by tax liability if not refundable
     if CDCC_refundable:
         c07180 = 0.
diff --git a/taxcalc/policy_current_law.json b/taxcalc/policy_current_law.json
index 896813e93..04d275d50 100644
--- a/taxcalc/policy_current_law.json
+++ b/taxcalc/policy_current_law.json
@@ -14074,21 +14074,21 @@
         "value": [
             {
                 "year": 2013,
-                "value": 35.0
+                "value": 0.350
             },
             {
                 "year": 2021,
-                "value": 50.0
+                "value": 0.500
             },
             {
                 "year": 2022,
-                "value": 35.0
+                "value": 0.350
             }
         ],
         "validators": {
             "range": {
                 "min": 0,
-                "max": 100
+                "max": 1
             }
         },
         "compatible_data": {
@@ -14108,13 +14108,13 @@
         "value": [
             {
                 "year": 2013,
-                "value": 20.0
+                "value": 0.2
             }
         ],
         "validators": {
             "range": {
                 "min": 0,
-                "max": 100
+                "max": 1
             }
         },
         "compatible_data": {
@@ -18104,4 +18104,4 @@
             "cps": true
         }
     }
-}
\ No newline at end of file
+}

From 25c5cfea7886d3a180e5bb8c2e41b01a3a6fcb41 Mon Sep 17 00:00:00 2001
From: duncanhobbs <duncan2012@gmail.com>
Date: Wed, 29 Sep 2021 14:07:42 -0400
Subject: [PATCH 02/22] Update documentation for CDCC_crt and CDCC_frt to
 reflect division by 100.

---
 docs/guide/policy_params.md | 38 ++++++++++++++++++-------------------
 1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/docs/guide/policy_params.md b/docs/guide/policy_params.md
index 9bb20f218..622ccb599 100644
--- a/docs/guide/policy_params.md
+++ b/docs/guide/policy_params.md
@@ -756,41 +756,41 @@ _Out-of-Range Action:_ error
 
 
 ####  `CDCC_crt`  
-_Description:_ The maximum percentage rate for the CDCC; this percentage rate decreases as AGI rises above the CDCC_ps level.  
+_Description:_ The maximum rate for the CDCC; this rate decreases as AGI rises above the CDCC_ps level.  
 _Has An Effect When Using:_ _PUF data:_ True _CPS data:_ True  
 _Can Be Inflation Indexed:_ False _Is Inflation Indexed:_ False  
 _Value Type:_ float  
 _Known Values:_  
-2013: 35.0  
-2014: 35.0  
-2015: 35.0  
-2016: 35.0  
-2017: 35.0  
-2018: 35.0  
-2019: 35.0  
-_Valid Range:_ min = 0 and max = 100  
+2013: 0.35  
+2014: 0.35  
+2015: 0.35  
+2016: 0.35  
+2017: 0.35  
+2018: 0.35  
+2019: 0.35  
+_Valid Range:_ min = 0 and max = 1  
 _Out-of-Range Action:_ error  
 
 
 ####  `CDCC_frt`  
-_Description:_ The minimum percentage rate for the first AGI phaseout of the CDCC.  
+_Description:_ The minimum rate for the first AGI phaseout of the CDCC.  
 _Has An Effect When Using:_ _PUF data:_ True _CPS data:_ True  
 _Can Be Inflation Indexed:_ False _Is Inflation Indexed:_ False  
 _Value Type:_ float  
 _Known Values:_  
-2013: 20.0  
-2014: 20.0  
-2015: 20.0  
-2016: 20.0  
-2017: 20.0  
-2018: 20.0  
-2019: 20.0  
-_Valid Range:_ min = 0 and max = 100  
+2013: 0.20  
+2014: 0.20  
+2015: 0.20  
+2016: 0.20  
+2017: 0.20  
+2018: 0.20  
+2019: 0.20  
+_Valid Range:_ min = 0 and max = 1  
 _Out-of-Range Action:_ error  
 
 
 ####  `CDCC_prt`  
-_Description:_ The CDCC credit rate is reduced by this many percentage points for each dollary of AGI over the phase-out thresholds.  
+_Description:_ The CDCC credit rate is reduced by this many percentage points for each dollar of AGI over the phase-out thresholds.  
 _Notes:_ In the law, the credit rate is reduced by 1 percentage point for every $2,000 of AGI over the limit.  
 _Has An Effect When Using:_ _PUF data:_ True _CPS data:_ True  
 _Can Be Inflation Indexed:_ False _Is Inflation Indexed:_ False  

From 473ae2a05384763d4a588ed26d5780d186d8df78 Mon Sep 17 00:00:00 2001
From: duncanhobbs <duncan2012@gmail.com>
Date: Tue, 5 Oct 2021 18:18:30 -0400
Subject: [PATCH 03/22] Update test_reforms.py with adjusted parameter values.

---
 taxcalc/tests/test_reforms.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/taxcalc/tests/test_reforms.py b/taxcalc/tests/test_reforms.py
index 0db6aafbc..d1151044d 100644
--- a/taxcalc/tests/test_reforms.py
+++ b/taxcalc/tests/test_reforms.py
@@ -146,7 +146,7 @@ def test_round_trip_reforms(fyear, tests_path):
          'CDCC_c': {2021: 8000, 2022: 3000},
          'CDCC_ps': {2021: 125000, 2022: 15000},
          'CDCC_ps2': {2021: 400000, 2022: 9e+99},
-         'CDCC_crt': {2021: 50.0, 2022: 35.0},
+         'CDCC_crt': {2021: 0.500, 2022: 0.350},
          'CDCC_refundable': {2021: True, 2022: False},
          'ALD_BusinessLosses_c': {
              2026: [283535.22, 567070.42, 283535.22, 283535.22, 567070.42],

From fac5f21202bcfe4f7b7bec9cc44ee419406cca0f Mon Sep 17 00:00:00 2001
From: duncanhobbs <duncan2012@gmail.com>
Date: Tue, 5 Oct 2021 18:47:39 -0400
Subject: [PATCH 04/22] Correct precision of CDCC_frt.

---
 taxcalc/policy_current_law.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/taxcalc/policy_current_law.json b/taxcalc/policy_current_law.json
index 04d275d50..4024eb5c5 100644
--- a/taxcalc/policy_current_law.json
+++ b/taxcalc/policy_current_law.json
@@ -14108,7 +14108,7 @@
         "value": [
             {
                 "year": 2013,
-                "value": 0.2
+                "value": 0.200
             }
         ],
         "validators": {

From 7fbd861da12a4fe1173ec2f2e8206f599874bad8 Mon Sep 17 00:00:00 2001
From: jdebacker <jason.debacker@gmail.com>
Date: Thu, 21 Oct 2021 06:42:06 -0400
Subject: [PATCH 05/22] make CDCC_prt a rate

---
 taxcalc/policy_current_law.json | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/taxcalc/policy_current_law.json b/taxcalc/policy_current_law.json
index 4024eb5c5..cc6d463b7 100644
--- a/taxcalc/policy_current_law.json
+++ b/taxcalc/policy_current_law.json
@@ -14063,8 +14063,8 @@
         }
     },
     "CDCC_crt": {
-        "title": "Child & dependent care credit phaseout percentage rate ceiling",
-        "description": "The maximum percentage rate for the CDCC; this percentage rate decreases as AGI rises above the CDCC_ps level.",
+        "title": "Child & dependent care credit phaseout rate ceiling",
+        "description": "The maximum rate for the CDCC; this rate decreases as AGI rises above the CDCC_ps level.",
         "notes": "",
         "section_1": "Nonrefundable Credits",
         "section_2": "Child And Dependent Care",
@@ -14097,8 +14097,8 @@
         }
     },
     "CDCC_frt": {
-        "title": "Child & dependent care credit phaseout percentage rate floor",
-        "description": "The minimum percentage rate for the first AGI phaseout of the CDCC.",
+        "title": "Child & dependent care credit phaseout rate floor",
+        "description": "The minimum rate for the first AGI phaseout of the CDCC.",
         "notes": "",
         "section_1": "Nonrefundable Credits",
         "section_2": "Child And Dependent Care",
@@ -14123,9 +14123,9 @@
         }
     },
     "CDCC_prt": {
-        "title": "Child & dependent care credit phaseout percentage rate",
-        "description": "The CDCC credit rate is reduced by this many percentage points for each dollary of AGI over the phase-out thresholds.",
-        "notes": "In the law, the credit rate is reduced by 1 percentage point for every $2,000 of AGI over the limit.",
+        "title": "Child & dependent care credit phaseout rate",
+        "description": "The CDCC credit rate is reduced by this many percentage points for each dollar of AGI over the phase-out thresholds.",
+        "notes": "In the law, the credit rate is reduced by 1 percentage point for every $2,000 of AGI over the limit. 0.01 / 2000 = 0.000005",
         "section_1": "Nonrefundable Credits",
         "section_2": "Child And Dependent Care",
         "indexable": false,
@@ -14134,7 +14134,7 @@
         "value": [
             {
                 "year": 2013,
-                "value": 0.0005
+                "value": 5e-06
             }
         ],
         "validators": {

From b4b174930085ca091ccf1db31bbf02485e75ac39 Mon Sep 17 00:00:00 2001
From: jdebacker <jason.debacker@gmail.com>
Date: Thu, 21 Oct 2021 06:42:35 -0400
Subject: [PATCH 06/22] update F2441 docstring

---
 taxcalc/calcfunctions.py | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/taxcalc/calcfunctions.py b/taxcalc/calcfunctions.py
index d4df6f8f7..c57de0b72 100644
--- a/taxcalc/calcfunctions.py
+++ b/taxcalc/calcfunctions.py
@@ -2119,15 +2119,23 @@ def F2441(MARS, earned_p, earned_s, f2441, CDCC_c, e32800,
     c00100: float
         Adjusted Gross Income (AGI)
     CDCC_ps: float
-        Child/dependent care credit phaseout start
+        Child/dependent care credit first phaseout start
+    CDCC_ps2: float
+        Child/dependent care credit second phaseout start
     CDCC_crt: float
-        Child/dependent care credit phaseout percentage rate ceiling
+        Child/dependent care credit phaseout rate ceiling
+    CDCC_frt: float
+        Child/dependent care credit phaseout rate floor
+    CDCC_prt: float
+        Child/dependent care credit phaseout rate
     c05800: float
         Total (regular + AMT) income tax liability before credits
     e07300: float
         Foreign tax credit from Form 1116
     c07180: float
         Credit for child and dependent care expenses from Form 2441
+    CDCC_refund: bool
+        Indicator for whether CDCC is refundable
 
     Returns
     -------
@@ -2159,6 +2167,7 @@ def F2441(MARS, earned_p, earned_s, f2441, CDCC_c, e32800,
         if c00100 > CDCC_ps2:
             crate = max(0., CDCC_frt -
                         max(((c00100 - CDCC_ps2) * CDCC_prt), 0.))
+
     c33200 = c33000 * crate
     # credit is limited by tax liability if not refundable
     if CDCC_refundable:

From 3cf3a216146018e0d52dcf7a06a3a1f951973355 Mon Sep 17 00:00:00 2001
From: Bodi Yang <byang89@wisc.edu>
Date: Tue, 3 Jan 2023 15:28:54 -0500
Subject: [PATCH 07/22] update documentation of policy parameters

---
 docs/guide/policy_params.md | 67 +++++++++++++++++++++++++++----------
 1 file changed, 49 insertions(+), 18 deletions(-)

diff --git a/docs/guide/policy_params.md b/docs/guide/policy_params.md
index 9bb20f218..72e70ed22 100644
--- a/docs/guide/policy_params.md
+++ b/docs/guide/policy_params.md
@@ -80,38 +80,69 @@ _Out-of-Range Action:_ error
 
 ### Medicare FICA
 
-####  `FICA_mc_trt`  
-_Description:_ Medicare FICA rate, including both employer and employee.  
+####  `FICA_mc_trt_employer`  
+_Description:_ Employer side Medicare FICA rate.
 _Has An Effect When Using:_ _PUF data:_ True _CPS data:_ True  
 _Can Be Inflation Indexed:_ False _Is Inflation Indexed:_ False  
 _Value Type:_ float  
 _Known Values:_  
-2013: 0.029  
-2014: 0.029  
-2015: 0.029  
-2016: 0.029  
-2017: 0.029  
-2018: 0.029  
-2019: 0.029  
+2013: 0.0145  
+2014: 0.0145  
+2015: 0.0145  
+2016: 0.0145  
+2017: 0.0145  
+2018: 0.0145  
+2019: 0.0145  
 _Valid Range:_ min = 0 and max = 1  
 _Out-of-Range Action:_ error  
 
+####  `FICA_mc_trt_employee`  
+_Description:_ Employee side Medicare FICA rate.
+_Has An Effect When Using:_ _PUF data:_ True _CPS data:_ True  
+_Can Be Inflation Indexed:_ False _Is Inflation Indexed:_ False  
+_Value Type:_ float  
+_Known Values:_  
+2013: 0.0145  
+2014: 0.0145  
+2015: 0.0145  
+2016: 0.0145  
+2017: 0.0145  
+2018: 0.0145  
+2019: 0.0145  
+_Valid Range:_ min = 0 and max = 1  
+_Out-of-Range Action:_ error 
 
 ### Social Security FICA
 
-####  `FICA_ss_trt`  
-_Description:_ Social Security FICA rate, including both employer and employee.  
+####  `FICA_ss_trt_employer`  
+_Description:_ Employer side Social Security FICA rate.  
+_Has An Effect When Using:_ _PUF data:_ True _CPS data:_ True  
+_Can Be Inflation Indexed:_ False _Is Inflation Indexed:_ False  
+_Value Type:_ float  
+_Known Values:_  
+2013: 0.062  
+2014: 0.062  
+2015: 0.062  
+2016: 0.062  
+2017: 0.062  
+2018: 0.062  
+2019: 0.062  
+_Valid Range:_ min = 0 and max = 1  
+_Out-of-Range Action:_ error  
+
+####  `FICA_ss_trt_employee`  
+_Description:_ Employee side Social Security FICA rate.  
 _Has An Effect When Using:_ _PUF data:_ True _CPS data:_ True  
 _Can Be Inflation Indexed:_ False _Is Inflation Indexed:_ False  
 _Value Type:_ float  
 _Known Values:_  
-2013: 0.124  
-2014: 0.124  
-2015: 0.124  
-2016: 0.124  
-2017: 0.124  
-2018: 0.124  
-2019: 0.124  
+2013: 0.062  
+2014: 0.062  
+2015: 0.062  
+2016: 0.062  
+2017: 0.062  
+2018: 0.062  
+2019: 0.062  
 _Valid Range:_ min = 0 and max = 1  
 _Out-of-Range Action:_ error  
 

From 73ee2702e8ce3a035efd844f4d959ee10ccea87a Mon Sep 17 00:00:00 2001
From: Bodi Yang <byang89@wisc.edu>
Date: Tue, 3 Jan 2023 16:36:42 -0500
Subject: [PATCH 08/22] update functions

---
 taxcalc/calcfunctions.py | 58 +++++++++++++++++++++++-----------------
 taxcalc/calculator.py    |  8 +++---
 taxcalc/parameters.py    |  2 +-
 3 files changed, 40 insertions(+), 28 deletions(-)

diff --git a/taxcalc/calcfunctions.py b/taxcalc/calcfunctions.py
index 54322ad13..a758e4f58 100644
--- a/taxcalc/calcfunctions.py
+++ b/taxcalc/calcfunctions.py
@@ -100,8 +100,9 @@ def BenefitPrograms(calc):
 
 @iterate_jit(nopython=True)
 def EI_PayrollTax(SS_Earnings_c, e00200p, e00200s, pencon_p, pencon_s,
-                  FICA_ss_trt, FICA_mc_trt, ALD_SelfEmploymentTax_hc,
-                  SS_Earnings_thd, SECA_Earnings_thd,
+                  FICA_ss_trt_employer, FICA_ss_trt_employee, 
+                  FICA_mc_trt_employer, FICA_mc_trt_employee, 
+                  ALD_SelfEmploymentTax_hc, SS_Earnings_thd, SECA_Earnings_thd,
                   e00900p, e00900s, e02100p, e02100s, k1bx14p,
                   k1bx14s, payrolltax, ptax_was, setax, c03260, ptax_oasdi,
                   sey, earned, earned_p, earned_s,
@@ -123,10 +124,14 @@ def EI_PayrollTax(SS_Earnings_c, e00200p, e00200s, pencon_p, pencon_s,
         Contributions to defined-contribution pension plans for taxpayer
     pencon_s: float
         Contributions to defined-contribution pension plans for spouse
-    FICA_ss_trt: float
-        Social security payroll tax rate, including both employer and employee
-    FICA_mc_trt: float
-        Medicare payroll tax rate, including both employer and employee
+    FICA_ss_trt_employer: float
+        Employer side social security payroll tax rate
+    FICA_ss_trt_employee: float
+        Employee side social security payroll tax rate    
+    FICA_mc_trt_employer: float
+        Employer side medicare payroll tax rate
+    FICA_mc_trt_employee: float
+        Employee side medicare payroll tax rate
     ALD_SelfEmploymentTax_hc: float
         Adjustment for self-employment tax haircut
         If greater than zero, reduces the employer equivalent portion of self-employment adjustment
@@ -218,22 +223,22 @@ def EI_PayrollTax(SS_Earnings_c, e00200p, e00200s, pencon_p, pencon_s,
     txearn_was_s = min(SS_Earnings_c, gross_was_s)
 
     # compute OASDI and HI payroll taxes on wage-and-salary income, FICA
-    ptax_ss_was_p = FICA_ss_trt * txearn_was_p
-    ptax_ss_was_s = FICA_ss_trt * txearn_was_s
-    ptax_mc_was_p = FICA_mc_trt * gross_was_p
-    ptax_mc_was_s = FICA_mc_trt * gross_was_s
+    ptax_ss_was_p = (FICA_ss_trt_employer + FICA_ss_trt_employee) * txearn_was_p
+    ptax_ss_was_s = (FICA_ss_trt_employer + FICA_ss_trt_employee) * txearn_was_s
+    ptax_mc_was_p = (FICA_mc_trt_employer + FICA_mc_trt_employee) * gross_was_p
+    ptax_mc_was_s = (FICA_mc_trt_employer + FICA_mc_trt_employee) * gross_was_s
     ptax_was = ptax_ss_was_p + ptax_ss_was_s + ptax_mc_was_p + ptax_mc_was_s
 
     # compute taxable self-employment income for OASDI SECA
-    sey_frac = 1.0 - 0.5 * (FICA_ss_trt + FICA_mc_trt)
+    sey_frac = 1.0 - 0.5 * (FICA_ss_trt_employer + FICA_ss_trt_employee + FICA_mc_trt_employer + FICA_mc_trt_employee)
     txearn_sey_p = min(max(0., sey_p * sey_frac), SS_Earnings_c - txearn_was_p)
     txearn_sey_s = min(max(0., sey_s * sey_frac), SS_Earnings_c - txearn_was_s)
 
     # compute self-employment tax on taxable self-employment income, SECA
-    setax_ss_p = FICA_ss_trt * txearn_sey_p
-    setax_ss_s = FICA_ss_trt * txearn_sey_s
-    setax_mc_p = FICA_mc_trt * max(0., sey_p * sey_frac)
-    setax_mc_s = FICA_mc_trt * max(0., sey_s * sey_frac)
+    setax_ss_p = (FICA_ss_trt_employer + FICA_ss_trt_employee) * txearn_sey_p
+    setax_ss_s = (FICA_ss_trt_employer + FICA_ss_trt_employee) * txearn_sey_s
+    setax_mc_p = (FICA_mc_trt_employer + FICA_mc_trt_employee) * max(0., sey_p * sey_frac)
+    setax_mc_s = (FICA_mc_trt_employer + FICA_mc_trt_employee) * max(0., sey_s * sey_frac)
     setax_p = setax_ss_p + setax_mc_p
     setax_s = setax_ss_s + setax_mc_s
     setax = setax_p + setax_s
@@ -246,13 +251,13 @@ def EI_PayrollTax(SS_Earnings_c, e00200p, e00200s, pencon_p, pencon_s,
     # compute extra OASDI payroll taxes on the portion of the sum
     # of wage-and-salary income and taxable self employment income
     # that exceeds SS_Earnings_thd
-    sey_frac = 1.0 - 0.5 * FICA_ss_trt
+    sey_frac = 1.0 - 0.5 * (FICA_ss_trt_employer + FICA_ss_trt_employee) 
     was_plus_sey_p = gross_was_p + max(0., sey_p * sey_frac)
     was_plus_sey_s = gross_was_s + max(0., sey_s * sey_frac)
     extra_ss_income_p = max(0., was_plus_sey_p - SS_Earnings_thd)
     extra_ss_income_s = max(0., was_plus_sey_s - SS_Earnings_thd)
-    extra_payrolltax = (extra_ss_income_p * FICA_ss_trt +
-                        extra_ss_income_s * FICA_ss_trt)
+    extra_payrolltax = (extra_ss_income_p * (FICA_ss_trt_employer + FICA_ss_trt_employee)  +
+                        extra_ss_income_s * (FICA_ss_trt_employer + FICA_ss_trt_employee))
 
     # compute part of total payroll taxes for filing unit
     # (the ptax_amc part of total payroll taxes for the filing unit is
@@ -1057,7 +1062,8 @@ def ItemDed(e17500_capped, e18400_capped, e18500_capped, e19200_capped,
 @iterate_jit(nopython=True)
 def AdditionalMedicareTax(e00200, MARS,
                           AMEDT_ec, sey, AMEDT_rt,
-                          FICA_mc_trt, FICA_ss_trt,
+                          FICA_mc_trt_employer, FICA_mc_trt_employee,
+                          FICA_ss_trt_employer, FICA_ss_trt_employee,
                           ptax_amc, payrolltax):
     """
     Computes Additional Medicare Tax (Form 8959) included in payroll taxes.
@@ -1070,10 +1076,14 @@ def AdditionalMedicareTax(e00200, MARS,
         Additional Medicare Tax earnings exclusion
     AMEDT_rt: float
         Additional Medicare Tax rate
-    FICA_ss_trt: float
-        FICA Social Security tax rate
-    FICA_mc_trt: float
-        FICA Medicare tax rate
+    FICA_ss_trt_employer: float
+        Employer side FICA Social Security tax rate
+    FICA_ss_trt_employee: float
+        Employee side FICA Social Security tax rate
+    FICA_mc_trt_employer: float
+        Employer side FICA Medicare tax rate
+    FICA_mc_trt_employee: float
+        Employee side FICA Medicare tax rate        
     e00200: float
         Wages and salaries
     sey: float
@@ -1090,7 +1100,7 @@ def AdditionalMedicareTax(e00200, MARS,
     payrolltax: float
         payroll tax augmented by Additional Medicare Tax
     """
-    line8 = max(0., sey) * (1. - 0.5 * (FICA_mc_trt + FICA_ss_trt))
+    line8 = max(0., sey) * (1. - 0.5 * (FICA_mc_trt_employer + FICA_mc_trt_employee + FICA_ss_trt_employer + FICA_ss_trt_employee))
     line11 = max(0., AMEDT_ec[MARS - 1] - e00200)
     ptax_amc = AMEDT_rt * (max(0., e00200 - AMEDT_ec[MARS - 1]) +
                            max(0., line8 - line11))
diff --git a/taxcalc/calculator.py b/taxcalc/calculator.py
index 092e15e28..af2abbd84 100644
--- a/taxcalc/calculator.py
+++ b/taxcalc/calculator.py
@@ -694,9 +694,11 @@ def mtr(self, variable_str='e00200p',
                 variable >= self.policy_param('SS_Earnings_thd')
             )
             adj = np.where(oasdi_taxed,
-                           0.5 * (self.policy_param('FICA_ss_trt') +
-                                  self.policy_param('FICA_mc_trt')),
-                           0.5 * self.policy_param('FICA_mc_trt'))
+                           0.5 * (self.policy_param('FICA_ss_trt_employer') +
+                                  self.policy_param('FICA_ss_trt_employee') +
+                                  self.policy_param('FICA_mc_trt_employer') +
+                                  self.policy_param('FICA_mc_trt_employee')),
+                           0.5 * (self.policy_param('FICA_mc_trt_employer') + self.policy_param('FICA_mc_trt_employee')))
         else:
             adj = 0.0
         # compute marginal tax rates
diff --git a/taxcalc/parameters.py b/taxcalc/parameters.py
index 13424566b..8ebbf04cb 100644
--- a/taxcalc/parameters.py
+++ b/taxcalc/parameters.py
@@ -61,7 +61,7 @@ class Parameters(pt.Parameters):
                 print(name, value)
 
             # parameter_indexing_CPI_offset [0.]
-            # FICA_ss_trt [0.124]
+            # FICA_ss_trt_employer [0.062]
             # SS_Earnings_c [113700.]
 
     Check out the ParamTools

From 8c9de96b0af51991bbd231d218ac9ad2459b58ee Mon Sep 17 00:00:00 2001
From: Bodi Yang <byang89@wisc.edu>
Date: Wed, 4 Jan 2023 10:08:25 -0500
Subject: [PATCH 09/22] update reform, tests files

---
 taxcalc/reforms/Larson2019.json | 29 +++++++++++++++++++----------
 taxcalc/reforms/ptaxes0.json    | 28 ++++++++++++++++++----------
 taxcalc/tests/reforms.json      |  5 +++--
 taxcalc/tests/test_policy.py    | 20 ++++++++++++++------
 4 files changed, 54 insertions(+), 28 deletions(-)

diff --git a/taxcalc/reforms/Larson2019.json b/taxcalc/reforms/Larson2019.json
index 7fb5f9520..e984c6337 100644
--- a/taxcalc/reforms/Larson2019.json
+++ b/taxcalc/reforms/Larson2019.json
@@ -10,18 +10,27 @@
 // Reform_Parameter_Map:
 // - 1: SS_thd50, SS_thd85
 // - 2: SS_Earnings_thd
-// - 3: FICA_ss_trt
+// - 3: FICA_ss_trt_employer, FICA_ss_trt_employee
 {
     "SS_thd50": {"2019": [50000, 100000, 50000, 50000, 50000]},
     "SS_thd85": {"2019": [50000, 100000, 50000, 50000, 50000]},
     "SS_Earnings_thd": {"2019": 400000},
-    "FICA_ss_trt": {"2020": 0.125,
-                    "2021": 0.126,
-                    "2022": 0.127,
-                    "2023": 0.128,
-                    "2024": 0.129,
-                    "2025": 0.130,
-                    "2026": 0.131,
-                    "2027": 0.132,
-                    "2028": 0.133}
+    "FICA_ss_trt_employer": {"2020": 0.0625,
+                             "2021": 0.063,
+                             "2022": 0.0635,
+                             "2023": 0.064,
+                             "2024": 0.0645,
+                             "2025": 0.065,
+                             "2026": 0.0655,
+                             "2027": 0.066,
+                             "2028": 0.0665},
+    "FICA_ss_trt_employee": {"2020": 0.0625,
+                             "2021": 0.063,
+                             "2022": 0.0635,
+                             "2023": 0.064,
+                             "2024": 0.0645,
+                             "2025": 0.065,
+                             "2026": 0.0655,
+                             "2027": 0.066,
+                             "2028": 0.0665}                
 }
diff --git a/taxcalc/reforms/ptaxes0.json b/taxcalc/reforms/ptaxes0.json
index 3bf989cb8..f209db519 100644
--- a/taxcalc/reforms/ptaxes0.json
+++ b/taxcalc/reforms/ptaxes0.json
@@ -1,6 +1,6 @@
 // Raise OASDI ("social security") and HI ("Medicare") payroll tax rates
-// : current law OASDI (employee+employer) rate is 0.124
-// : current law    HI (employee+employer) rate is 0.029
+// : current law OASDI (employee+employer) rate is 0.124, with 0.062 on employer and employee side
+// : current law    HI (employee+employer) rate is 0.029, with 0.0145 on employer and employee side
 // Reform_Baseline: 2017_law.json
 // Reform_Description:
 // -  raise OASDI payroll tax rate in 2018 and 2020 (1)
@@ -8,7 +8,7 @@
 // Reform_Parameter_Map:
 // - 1: FICA_ss_trt
 // - 2: FICA_mc_trt
-// NOTE: this reform produces the following rates by year:
+// NOTE: this reform produces the following rates (employee+employer) by year:
 //       2017:  0.124  0.029
 //       2018:  0.130  0.029
 //       2019:  0.130  0.030
@@ -16,12 +16,20 @@
 //       2021:  0.140  0.032
 //       2022:  0.140  0.032
 {
-    "FICA_ss_trt": {
-        "2018": 0.130,
-        "2020": 0.140
+    "FICA_ss_trt_employer": {
+        "2018": 0.065,
+        "2020": 0.070
     },
-    "FICA_mc_trt": {
-        "2019": 0.030,
-        "2021": 0.032
-    }        
+    "FICA_ss_trt_employee": {
+        "2018": 0.065,
+        "2020": 0.070
+    },
+    "FICA_mc_trt_employer": {
+        "2019": 0.015,
+        "2021": 0.016
+    },
+    "FICA_mc_trt_employee": {
+        "2019": 0.015,
+        "2021": 0.016
+    }         
 }
diff --git a/taxcalc/tests/reforms.json b/taxcalc/tests/reforms.json
index 2c1e5f8cf..5e1cd612e 100644
--- a/taxcalc/tests/reforms.json
+++ b/taxcalc/tests/reforms.json
@@ -2,8 +2,9 @@
   "1": {
       "baseline": "2017_law.json",
       "start_year": 2015,
-      "value": {"FICA_ss_trt": 0.134},
-      "name": "Increase OASDI payroll tax rate by 1 pts",
+      "value": {"FICA_ss_trt_employer": 0.067,
+                "FICA_ss_trt_employee": 0.067},
+      "name": "Increase OASDI payroll tax rate by 1 pts, split evenly on employer and employee sides",
       "output_type": "payrolltax",
       "compare_with": {}
   },
diff --git a/taxcalc/tests/test_policy.py b/taxcalc/tests/test_policy.py
index 9b21fe1dd..6e9d28154 100644
--- a/taxcalc/tests/test_policy.py
+++ b/taxcalc/tests/test_policy.py
@@ -72,14 +72,22 @@ def test_json_reform_url():
     reform_str = """
     {
         // raise FICA payroll tax rate in 2018 and 2020
-        "FICA_ss_trt": {
-            "2018": 0.130,
-            "2020": 0.140
+        "FICA_ss_trt_employer": {
+            "2018": 0.065,
+            "2020": 0.070
+        },
+        "FICA_ss_trt_employee": {
+            "2018": 0.065,
+            "2020": 0.070
         },
         // raise Medicare payroll tax rate in 2019 and 2021
-        "FICA_mc_trt": {
-            "2019": 0.030,
-            "2021": 0.032
+        "FICA_mc_trt_employer": {
+            "2019": 0.015,
+            "2021": 0.016
+        },
+        "FICA_mc_trt_employee": {
+            "2019": 0.015,
+            "2021": 0.016
         }
     }
     """

From d25902f72007c71af5869ca20bf2db7ac2936101 Mon Sep 17 00:00:00 2001
From: Bodi Yang <byang89@wisc.edu>
Date: Wed, 4 Jan 2023 14:20:35 -0500
Subject: [PATCH 10/22] update parameter in policy law file

---
 taxcalc/policy_current_law.json | 72 ++++++++++++++++++++++++++++-----
 1 file changed, 62 insertions(+), 10 deletions(-)

diff --git a/taxcalc/policy_current_law.json b/taxcalc/policy_current_law.json
index 37b4f96e8..ce3f92f77 100644
--- a/taxcalc/policy_current_law.json
+++ b/taxcalc/policy_current_law.json
@@ -117,9 +117,9 @@
             "cps": true
         }
     },
-    "FICA_ss_trt": {
-        "title": "Social Security payroll tax rate",
-        "description": "Social Security FICA rate, including both employer and employee.",
+    "FICA_ss_trt_employer": {
+        "title": "Employer side Social Security payroll tax rate",
+        "description": "Employer side Social Security FICA rate, including both employer and employee.",
         "notes": "",
         "section_1": "Payroll Taxes",
         "section_2": "Social Security FICA",
@@ -129,13 +129,39 @@
         "value": [
             {
                 "year": 2013,
-                "value": 0.124
+                "value": 0.062
             }
         ],
         "validators": {
             "range": {
                 "min": 0,
-                "max": 1
+                "max": 0.5
+            }
+        },
+        "compatible_data": {
+            "puf": true,
+            "cps": true
+        }
+    },
+    "FICA_ss_trt_employee": {
+        "title": "Employee side Social Security payroll tax rate",
+        "description": "Employee side Social Security FICA rate, including both employer and employee.",
+        "notes": "",
+        "section_1": "Payroll Taxes",
+        "section_2": "Social Security FICA",
+        "indexable": false,
+        "indexed": false,
+        "type": "float",
+        "value": [
+            {
+                "year": 2013,
+                "value": 0.062
+            }
+        ],
+        "validators": {
+            "range": {
+                "min": 0,
+                "max": 0.5
             }
         },
         "compatible_data": {
@@ -257,9 +283,9 @@
             "cps": true
         }
     },
-    "FICA_mc_trt": {
-        "title": "Medicare payroll tax rate",
-        "description": "Medicare FICA rate, including both employer and employee.",
+    "FICA_mc_trt_employer": {
+        "title": "Employer side Medicare payroll tax rate",
+        "description": "Employer side Medicare FICA rate, including both employer and employee.",
         "notes": "",
         "section_1": "Payroll Taxes",
         "section_2": "Medicare FICA",
@@ -269,13 +295,39 @@
         "value": [
             {
                 "year": 2013,
-                "value": 0.029
+                "value": 0.0145
             }
         ],
         "validators": {
             "range": {
                 "min": 0,
-                "max": 1
+                "max": 0.5
+            }
+        },
+        "compatible_data": {
+            "puf": true,
+            "cps": true
+        }
+    },
+    "FICA_mc_trt_employee": {
+        "title": "Employee side Medicare payroll tax rate",
+        "description": "Employee side Medicare FICA rate, including both employer and employee.",
+        "notes": "",
+        "section_1": "Payroll Taxes",
+        "section_2": "Medicare FICA",
+        "indexable": false,
+        "indexed": false,
+        "type": "float",
+        "value": [
+            {
+                "year": 2013,
+                "value": 0.0145
+            }
+        ],
+        "validators": {
+            "range": {
+                "min": 0,
+                "max": 0.5
             }
         },
         "compatible_data": {

From 0969fc89dc09abca0fd3f66fadb6def90d7deb26 Mon Sep 17 00:00:00 2001
From: Bodi Yang <byang89@wisc.edu>
Date: Wed, 11 Jan 2023 11:03:15 -0500
Subject: [PATCH 11/22] update testing reform file

---
 taxcalc/tests/reforms.json | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/taxcalc/tests/reforms.json b/taxcalc/tests/reforms.json
index 5e1cd612e..6e6580849 100644
--- a/taxcalc/tests/reforms.json
+++ b/taxcalc/tests/reforms.json
@@ -21,7 +21,8 @@
   "3": {
       "baseline": "2017_law.json",
       "start_year": 2015,
-      "value": {"FICA_mc_trt": 0.039},
+      "value": {"FICA_mc_trt_employer": 0.0195,
+                "FICA_mc_trt_employee": 0.0195},
       "name": "Increase HI payroll tax rate by 1 pts",
       "output_type": "payrolltax",
       "compare_with": {"Budget Options": [73, 77, 82, 87]}

From 8255631e36a2fecac504e8a96e5cb9940b157279 Mon Sep 17 00:00:00 2001
From: Bodi Yang <byang89@wisc.edu>
Date: Wed, 11 Jan 2023 20:19:00 -0500
Subject: [PATCH 12/22] solve payroll testing problem

---
 taxcalc/tests/test_calcfunctions.py | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/taxcalc/tests/test_calcfunctions.py b/taxcalc/tests/test_calcfunctions.py
index 160533b4f..cf1aa1e28 100644
--- a/taxcalc/tests/test_calcfunctions.py
+++ b/taxcalc/tests/test_calcfunctions.py
@@ -223,22 +223,22 @@ def test_StdDed(test_tuple, expected_value, skip_jit):
     assert np.allclose(test_value, expected_value)
 
 
-tuple1 = (120000, 10000, 15000, 100, 2000, 0.12, 0.03, 0, 99999999999,
-          400, 0, 0, 0, 0, 0, 0, None, None, None, None, None, None,
+tuple1 = (120000, 10000, 15000, 100, 2000, 0.06, 0.06, 0.015, 0.015, 0, 99999999999, 
+          400, 0, 0, 0, 0, 0, 0, None, None, None, None, None, None, 
           None, None, None, None, None)
-tuple2 = (120000, 10000, 15000, 100, 2000, 0.12, 0.03, 0, 99999999999,
+tuple2 = (120000, 10000, 15000, 100, 2000, 0.06, 0.06, 0.015, 0.015, 0, 99999999999,
           400, 2000, 0, 10000, 0, 0, 3000, None, None, None, None, None,
           None, None, None, None, None, None)
-tuple3 = (120000, 150000, 15000, 100, 2000, 0.12, 0.03, 0, 99999999999,
+tuple3 = (120000, 150000, 15000, 100, 2000, 0.06, 0.06, 0.015, 0.015, 0, 99999999999,
           400, 2000, 0, 10000, 0, 0, 3000, None, None, None, None, None,
           None, None, None, None, None, None)
-tuple4 = (120000, 500000, 15000, 100, 2000, 0.12, 0.03, 0, 400000,
+tuple4 = (120000, 500000, 15000, 100, 2000, 0.06, 0.06, 0.015, 0.015, 0, 400000,
           400, 2000, 0, 10000, 0, 0, 3000, None, None, None, None, None,
           None, None, None, None, None, None)
-tuple5 = (120000, 10000, 15000, 100, 2000, 0.12, 0.03, 0, 99999999999,
+tuple5 = (120000, 10000, 15000, 100, 2000, 0.06, 0.06, 0.015, 0.015, 0, 99999999999,
           400, 300, 0, 0, 0, 0, 0, None, None, None, None, None,
           None, None, None, None, None, None)
-tuple6 = (120000, 10000, 15000, 100, 2000, 0.12, 0.03, 0, 99999999999,
+tuple6 = (120000, 10000, 15000, 100, 2000, 0.06, 0.06, 0.015, 0.015, 0, 99999999999,
           400, 0, 0, 0, 0, -40000, 0, None, None, None, None, None,
           None, None, None, None, None, None)
 expected1 = (0, 4065, 4065, 0, 0, 3252, 25000, 10000, 15000, 10100,

From dc5f6b6707bf63c5839f7390501bfe390cc9c6b9 Mon Sep 17 00:00:00 2001
From: jdebacker <jason.debacker@gmail.com>
Date: Thu, 19 Jan 2023 12:27:34 -0500
Subject: [PATCH 13/22] change CDCC rate scale

---
 taxcalc/reforms/ARPA.json | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/taxcalc/reforms/ARPA.json b/taxcalc/reforms/ARPA.json
index b61e52f80..b162b8f1c 100644
--- a/taxcalc/reforms/ARPA.json
+++ b/taxcalc/reforms/ARPA.json
@@ -59,8 +59,8 @@
                 "2022": 15000},
     "CDCC_ps2": {"2021": 400000,
                  "2022": 9e+99},
-    "CDCC_crt": {"2021": 50.0,
-                 "2022": 35.0},
+    "CDCC_crt": {"2021": 0.5,
+                 "2022": 0.35},
     "CDCC_refundable": {"2021": true,
                         "2022": false},
     "ALD_BusinessLosses_c": {"2026": [283535.22, 567070.42, 283535.22, 283535.22, 567070.42],

From ebf0cfa1b9e71ef96f0befc36029f07d0443ceca Mon Sep 17 00:00:00 2001
From: Bodi Yang <byang89@wisc.edu>
Date: Thu, 30 May 2024 10:26:58 -0400
Subject: [PATCH 14/22] release doc

---
 docs/about/releases.md | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/docs/about/releases.md b/docs/about/releases.md
index 1677e0d7d..064f2d27b 100644
--- a/docs/about/releases.md
+++ b/docs/about/releases.md
@@ -3,6 +3,20 @@ Release history
 Go [here](https://github.com/PSLmodels/Tax-Calculator/pulls?q=is%3Apr+is%3Aclosed)
 for a complete commit history.
 
+2024-06-01 Release 4.0.0
+------------------------
+(last merged pull request is
+[#2749](https://github.com/PSLmodels/Tax-Calculator/pull/2749))
+
+**This is a major release with changes that make Tax-Calculator incompatible with earlier releases.**
+
+**API Changes**
+- Reframewrok of the payroll tax policy parameters: Payroll tax parameters are split into the employer side and employee side ~ `FICA_mc_trt`, `FICA_ss_trt` are replaced by `FICA_mc_trt_employer`, `FICA_mc_trt_employee`, `FICA_ss_trt_employer` and `FICA_ss_trt_employee`. [[#2669](https://github.com/PSLmodels/Tax-Calculator/pull/2669) by Bodi Yang]
+- CDCC rate scale (`CDCC_crt`, `CDCC_frt`) changed from 0~1 to 0~100. [[#2628](https://github.com/PSLmodels/Tax-Calculator/pull/2628) by Duncan Hobbs and [#2671](https://github.com/PSLmodels/Tax-Calculator/pull/2671) by Jason DeBacker]
+
+**New Features**
+- Tax-Calculator 4.0.0 starts to incorporate with new [Taxcalc-Payroll](https://github.com/bodiyang/Taxcalc-Payroll) model, micro-simulation model focusing on payroll tax analysis. New features include (1) payroll tax reform simulation upon either employer side or employee side; (2) employer side payroll tax offset. [[Taxcalc-Payroll](https://github.com/bodiyang/Taxcalc-Payroll) developed by Bodi Yang]
+
 2024-05-10 Release 3.6.0
 ------------------------
 (last merged pull request is

From 8ab58fc2f58e2e1531741243782f84fb65c084b4 Mon Sep 17 00:00:00 2001
From: Bodi Yang <byang89@wisc.edu>
Date: Thu, 30 May 2024 10:33:42 -0400
Subject: [PATCH 15/22] update version

---
 docs/index.md             | 2 +-
 setup.py                  | 2 +-
 taxcalc.egg-info/PKG-INFO | 2 +-
 taxcalc/__init__.py       | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/docs/index.md b/docs/index.md
index d1c2b8f22..13ddb601f 100644
--- a/docs/index.md
+++ b/docs/index.md
@@ -57,7 +57,7 @@ The cross-model validation work with NBER's TAXSIM-27 model is described
 
 ## Latest release
 
-{doc}`3.6.0 (2024-05-10) <about/releases>`
+{doc}`4.0.0 (2024-06-01) <about/releases>`
 
 If you are already using Tax-Calculator, upgrade using the following command:
 
diff --git a/setup.py b/setup.py
index 90891cb60..052cf4884 100644
--- a/setup.py
+++ b/setup.py
@@ -3,7 +3,7 @@
 with open("README.md") as f:
     longdesc = f.read()
 
-version = "3.6.0"
+version = "4.0.0"
 
 config = {
     "description": "Tax Calculator",
diff --git a/taxcalc.egg-info/PKG-INFO b/taxcalc.egg-info/PKG-INFO
index b06f6189d..faa573225 100644
--- a/taxcalc.egg-info/PKG-INFO
+++ b/taxcalc.egg-info/PKG-INFO
@@ -1,6 +1,6 @@
 Metadata-Version: 2.1
 Name: taxcalc
-Version: 3.6.0
+Version: 4.0.0
 Summary: taxcalc
 Home-page: https://github.com/PSLmodels/Tax-Calculator
 Download-URL: https://github.com/PSLmodels/Tax-Calculator
diff --git a/taxcalc/__init__.py b/taxcalc/__init__.py
index d77f9f8e1..203473408 100644
--- a/taxcalc/__init__.py
+++ b/taxcalc/__init__.py
@@ -14,4 +14,4 @@
 from taxcalc.utils import *
 from taxcalc.cli import *
 
-__version__ = '3.6.0'
+__version__ = '4.0.0'

From ee589b9f3b907a75244cdf289e8354a048d9551c Mon Sep 17 00:00:00 2001
From: Bodi Yang <byang89@wisc.edu>
Date: Mon, 3 Jun 2024 14:39:40 -0400
Subject: [PATCH 16/22] change documentation

---
 docs/about/releases.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/about/releases.md b/docs/about/releases.md
index 064f2d27b..97e7d206c 100644
--- a/docs/about/releases.md
+++ b/docs/about/releases.md
@@ -11,7 +11,7 @@ for a complete commit history.
 **This is a major release with changes that make Tax-Calculator incompatible with earlier releases.**
 
 **API Changes**
-- Reframewrok of the payroll tax policy parameters: Payroll tax parameters are split into the employer side and employee side ~ `FICA_mc_trt`, `FICA_ss_trt` are replaced by `FICA_mc_trt_employer`, `FICA_mc_trt_employee`, `FICA_ss_trt_employer` and `FICA_ss_trt_employee`. [[#2669](https://github.com/PSLmodels/Tax-Calculator/pull/2669) by Bodi Yang]
+- Apply a new framework for the payroll tax policy parameters: Payroll tax parameters are split into the employer side and employee side ~ `FICA_mc_trt`, `FICA_ss_trt` are replaced by `FICA_mc_trt_employer`, `FICA_mc_trt_employee`, `FICA_ss_trt_employer` and `FICA_ss_trt_employee`. [[#2669](https://github.com/PSLmodels/Tax-Calculator/pull/2669) by Bodi Yang]
 - CDCC rate scale (`CDCC_crt`, `CDCC_frt`) changed from 0~1 to 0~100. [[#2628](https://github.com/PSLmodels/Tax-Calculator/pull/2628) by Duncan Hobbs and [#2671](https://github.com/PSLmodels/Tax-Calculator/pull/2671) by Jason DeBacker]
 
 **New Features**

From 50ae0c8f09d448480bd0b0ba23ba432e5a42be43 Mon Sep 17 00:00:00 2001
From: "martin.holmer@gmail.com" <martin.holmer@gmail.com>
Date: Tue, 4 Jun 2024 13:07:39 -0400
Subject: [PATCH 17/22] Add test_tmdcsv.py pytest file

---
 Makefile                     |  2 +-
 taxcalc/records.py           |  2 +-
 taxcalc/tests/conftest.py    | 10 ++++++++++
 taxcalc/tests/test_tmdcsv.py | 38 ++++++++++++++++++++++++++++++++++++
 4 files changed, 50 insertions(+), 2 deletions(-)
 create mode 100644 taxcalc/tests/test_tmdcsv.py

diff --git a/Makefile b/Makefile
index 2d9abe0bd..dcf83aeb9 100644
--- a/Makefile
+++ b/Makefile
@@ -13,7 +13,7 @@ help:
 	@echo "clean      : remove .pyc files and local taxcalc package"
 	@echo "package    : build and install local package"
 	@echo "pytest-cps : generate report for and cleanup after"
-	@echo "             pytest -m 'not requires_pufcsv and not pre_release'"
+	@echo "             pytest -m 'not requires_pufcsv and not requires_tmdcsv and not pre_release'"
 	@echo "pytest     : generate report for and cleanup after"
 	@echo "             pytest -m 'not pre_release'"
 	@echo "pytest-all : generate report for and cleanup after"
diff --git a/taxcalc/records.py b/taxcalc/records.py
index fedec143f..cc947f90a 100644
--- a/taxcalc/records.py
+++ b/taxcalc/records.py
@@ -227,7 +227,7 @@ def cps_constructor(data=None,
     @staticmethod
     def tmd_constructor(data,  # path to tmd.csv file or dataframe
                         gfactors=GrowFactors(),
-                        exact_calculations=False):  # pragma: no cover
+                        exact_calculations=False):
         """
         Static method returns a Records object instantiated with TMD
         input data.  This works in a analogous way to Records(), which
diff --git a/taxcalc/tests/conftest.py b/taxcalc/tests/conftest.py
index 06c334874..cb7c98aaf 100644
--- a/taxcalc/tests/conftest.py
+++ b/taxcalc/tests/conftest.py
@@ -53,6 +53,16 @@ def puf_subsample(puf_fullsample):
     return puf_fullsample.sample(frac=0.05, random_state=2222)
 
 
+@pytest.fixture(scope='session')
+def tmd_path(tests_path):
+    return os.path.join(tests_path, '..', '..', 'tmd.csv')
+
+
+@pytest.fixture(scope='session')
+def tmd_fullsample(tmd_path):
+    return pandas.read_csv(tmd_path)
+
+
 @pytest.fixture(scope='session', name='test_reforms_init')
 def fixture_test_reforms(tests_path):
     """
diff --git a/taxcalc/tests/test_tmdcsv.py b/taxcalc/tests/test_tmdcsv.py
new file mode 100644
index 000000000..6eb350f5c
--- /dev/null
+++ b/taxcalc/tests/test_tmdcsv.py
@@ -0,0 +1,38 @@
+"""
+Tests of Tax-Calculator using tmd.csv input.
+
+Note that the tmd.csv file that is required to run this program has
+been constructed in the PSLmodels tax-microdata repository using the
+2015 IRS SOI PUF file and recent Census CPS data.  If you have
+acquired from IRS the 2015 SOI PUF file and want to execute this program,
+contact the Tax-Calculator development team to discuss your options.
+
+Read Tax-Calculator/TESTING.md for details.
+"""
+# CODING-STYLE CHECKS:
+# pycodestyle test_tmdcsv.py
+# pylint --disable=locally-disabled test_tmdcsv.py
+
+import pytest
+# pylint: disable=import-error
+from taxcalc import Policy, Records, Calculator
+
+
+@pytest.mark.requires_tmdcsv
+def test_tmd_input(tmd_fullsample):
+    """
+    Test Tax-Calculator using full-sample tmd.csv file.
+    """
+    taxyear = 2022
+    # create a Policy object with current-law policy parameters
+    pol = Policy()
+    # create a Records object containing all tmd.csv input records
+    recs = Records.tmd_constructor(data=tmd_fullsample)
+    # create a Calculator object using current-law policy and tmd records
+    calc = Calculator(policy=pol, records=recs)
+    calc.advance_to_year(taxyear)
+    calc.calc_all()
+    assert calc.data_year == Records.TMDCSV_YEAR
+    assert calc.current_year == taxyear
+    inctax = calc.weighted_total('iitax')
+    assert inctax > 0

From 87861f8bd9e5a987f6003bb8b9bc58948a7811ab Mon Sep 17 00:00:00 2001
From: "martin.holmer@gmail.com" <martin.holmer@gmail.com>
Date: Tue, 4 Jun 2024 13:18:49 -0400
Subject: [PATCH 18/22] Add back no-cover pragma because test is
 requires_tmdcsv

---
 taxcalc/records.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/taxcalc/records.py b/taxcalc/records.py
index cc947f90a..fedec143f 100644
--- a/taxcalc/records.py
+++ b/taxcalc/records.py
@@ -227,7 +227,7 @@ def cps_constructor(data=None,
     @staticmethod
     def tmd_constructor(data,  # path to tmd.csv file or dataframe
                         gfactors=GrowFactors(),
-                        exact_calculations=False):
+                        exact_calculations=False):  # pragma: no cover
         """
         Static method returns a Records object instantiated with TMD
         input data.  This works in a analogous way to Records(), which

From 96e9f169d213d9b6322b67c5136fc5325ca4e47c Mon Sep 17 00:00:00 2001
From: Bodi Yang <byang89@wisc.edu>
Date: Wed, 5 Jun 2024 09:05:19 -0400
Subject: [PATCH 19/22] releases.md

---
 docs/about/releases.md | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/docs/about/releases.md b/docs/about/releases.md
index 97e7d206c..7cf33986d 100644
--- a/docs/about/releases.md
+++ b/docs/about/releases.md
@@ -15,7 +15,8 @@ for a complete commit history.
 - CDCC rate scale (`CDCC_crt`, `CDCC_frt`) changed from 0~1 to 0~100. [[#2628](https://github.com/PSLmodels/Tax-Calculator/pull/2628) by Duncan Hobbs and [#2671](https://github.com/PSLmodels/Tax-Calculator/pull/2671) by Jason DeBacker]
 
 **New Features**
-- Tax-Calculator 4.0.0 starts to incorporate with new [Taxcalc-Payroll](https://github.com/bodiyang/Taxcalc-Payroll) model, micro-simulation model focusing on payroll tax analysis. New features include (1) payroll tax reform simulation upon either employer side or employee side; (2) employer side payroll tax offset. [[Taxcalc-Payroll](https://github.com/bodiyang/Taxcalc-Payroll) developed by Bodi Yang]
+- Ablility to perform payroll tax reform upon either employer side or employee side. [by Bodi Yang]
+
 
 2024-05-10 Release 3.6.0
 ------------------------

From cb7b95ac4072da4296c0d3b3c9197551f1fce836 Mon Sep 17 00:00:00 2001
From: Bodi Yang <byang89@wisc.edu>
Date: Wed, 5 Jun 2024 09:06:51 -0400
Subject: [PATCH 20/22] update release file

---
 docs/about/releases.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/about/releases.md b/docs/about/releases.md
index 7cf33986d..3b8818c22 100644
--- a/docs/about/releases.md
+++ b/docs/about/releases.md
@@ -6,7 +6,7 @@ for a complete commit history.
 2024-06-01 Release 4.0.0
 ------------------------
 (last merged pull request is
-[#2749](https://github.com/PSLmodels/Tax-Calculator/pull/2749))
+[#2752](https://github.com/PSLmodels/Tax-Calculator/pull/2752))
 
 **This is a major release with changes that make Tax-Calculator incompatible with earlier releases.**
 

From 5e43e0a859571623c4919f0269dfe2495bd43f89 Mon Sep 17 00:00:00 2001
From: "martin.holmer@gmail.com" <martin.holmer@gmail.com>
Date: Wed, 5 Jun 2024 12:12:32 -0400
Subject: [PATCH 21/22] Revise GrowFactor constructor to handle custom
 growfactors files.

---
 taxcalc/growfactors.py | 35 +++++++++++++++++++----------------
 1 file changed, 19 insertions(+), 16 deletions(-)

diff --git a/taxcalc/growfactors.py b/taxcalc/growfactors.py
index 7a6223505..435fe5149 100644
--- a/taxcalc/growfactors.py
+++ b/taxcalc/growfactors.py
@@ -17,14 +17,15 @@ class GrowFactors():
 
     Parameters
     ----------
-    growfactors_filename: string
-        string is name of CSV file in which grow factors reside;
-        default value is name of file containing baseline grow factors.
+    growfactors_filename: None or string
+        string is path to the CSV file in which grow factors reside;
+        default value of None uses file containing baseline grow factors.
 
     Raises
     ------
     ValueError:
-        if growfactors_filename is not a string.
+        if growfactors_filename is neither None or a string.
+        if growfactors_filename string points to a non-existent file.
 
     Returns
     -------
@@ -33,7 +34,7 @@ class instance: GrowFactors
     Notes
     -----
     Typical usage is "gfactor = GrowFactors()", which produces an object
-    containing growth factors in the GrowFactors.FILE_NAME file.
+    containing baseline growth factors in the GrowFactors.FILE_NAME file.
     """
 
     FILE_NAME = 'growfactors.csv'
@@ -48,17 +49,19 @@ class instance: GrowFactors
                        'ABENSSI', 'ABENSNAP', 'ABENWIC',
                        'ABENHOUSING', 'ABENTANF', 'ABENVET'])
 
-    def __init__(self, growfactors_filename=FILE_NAME):
+    def __init__(self, growfactors_filename=None):
         # read grow factors from specified growfactors_filename
         gfdf = pd.DataFrame()
-        if isinstance(growfactors_filename, str):
-            full_filename = os.path.join(GrowFactors.FILE_PATH,
-                                         growfactors_filename)
-            if os.path.isfile(full_filename):
-                gfdf = pd.read_csv(full_filename, index_col='YEAR')
-            else:  # find file in package
-                gfdf = read_egg_csv(os.path.basename(growfactors_filename),
-                                    index_col='YEAR')  # pragma: no cover
+        if growfactors_filename is None:
+            # read baseline growfactor from package
+            gfdf = read_egg_csv(GrowFactors.FILE_NAME,
+                                index_col='YEAR')  # pragma: no cover
+        elif isinstance(growfactors_filename, str):
+            if os.path.isfile(growfactors_filename):
+                gfdf = pd.read_csv(growfactors_filename, index_col='YEAR')
+            else:  # file does not exist
+                msg = f'growfactors file {growfactors_filename} does not exist'
+                raise ValueError(msg)
         else:
             raise ValueError('growfactors_filename is not a string')
         assert isinstance(gfdf, pd.DataFrame)
@@ -143,7 +146,7 @@ def factor_value(self, name, year):
         if year > self.last_year:
             msg = 'year={} > GrowFactors.last_year={}'
             raise ValueError(msg.format(year, self.last_year))
-        return self.gfdf.loc[year,name]
+        return self.gfdf.loc[year, name]
 
     def update(self, name, year, diff):
         """
@@ -156,4 +159,4 @@ def update(self, name, year, diff):
         assert year >= self.first_year
         assert year <= self.last_year
         assert isinstance(diff, float)
-        self.gfdf.loc[year,name] += diff
+        self.gfdf.loc[year, name] += diff

From afb7df143de6905bce7f891ba32de6f5ad34d82d Mon Sep 17 00:00:00 2001
From: "martin.holmer@gmail.com" <martin.holmer@gmail.com>
Date: Wed, 5 Jun 2024 16:28:07 -0400
Subject: [PATCH 22/22] Add another test to test_growfactors.py

---
 taxcalc/tests/test_growfactors.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/taxcalc/tests/test_growfactors.py b/taxcalc/tests/test_growfactors.py
index 8c4771b8b..5e0e7d163 100644
--- a/taxcalc/tests/test_growfactors.py
+++ b/taxcalc/tests/test_growfactors.py
@@ -32,6 +32,8 @@ def test_improper_usage(bad_gf_file):
     """
     with pytest.raises(ValueError):
         gfo = GrowFactors(dict())
+    with pytest.raises(ValueError):
+        gfo = GrowFactors('non_existent_file.csv')
     with pytest.raises(ValueError):
         gfo = GrowFactors(bad_gf_file.name)
     gfo = GrowFactors()