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Merge pull request #2466 from Peter-Metz/new_ppp
New ppp.py
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| Original file line number | Diff line number | Diff line change |
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| """ | ||
| Policy parameter projection script, which calculates future policy parameter | ||
| values under TCJA and which should be used when the following happens: | ||
| (1) the inflation factor values change in growfactors.csv, or | ||
| (2) the last known historical values of policy parameters are updated, | ||
| in which case the byear parameter (see below) should be incremented. | ||
| Policy parameter projection script, which calculates policy parameter | ||
| values that were changed by TCJA and will revert to their pre-TCJA | ||
| values in 2026 (adjusted for inflation). The script should be run | ||
| when the inflation factor values change in growfactors.csv. | ||
| USAGE: $ python ppp.py | ||
| OUTPUT: ppp.old -- contains old parameter values in policy_current_law.json | ||
| ppp.new -- contains new parameter values that should now be used | ||
| Note: running this script will write the new 2026 parameter values | ||
| directly to policy_current_law.json. | ||
| """ | ||
| from taxcalc import Policy | ||
| from taxcalc import * | ||
| import json | ||
|
|
||
| # specify year constants (only byear should vary) | ||
| syear = Policy.JSON_START_YEAR | ||
| pyear = 2017 # prior year before TCJA first implemented | ||
| byear = 2019 # base year: year for last known historical parameter values | ||
| fyear = 2026 # final year in which parameter values revert to pre-TCJA values | ||
| params = Policy() | ||
|
|
||
| # ensure proper relationship between year constants | ||
| assert pyear == 2017 | ||
| assert fyear == 2026 | ||
| assert byear > pyear and byear < fyear | ||
| # parameters that will revert | ||
| long_params = ['II_brk7', 'II_brk6', 'II_brk5', 'II_brk4', | ||
| 'II_brk3', 'II_brk2', 'II_brk1', | ||
| 'PT_brk7', 'PT_brk6', 'PT_brk5', 'PT_brk4', | ||
| 'PT_brk3', 'PT_brk2', 'PT_brk1', | ||
| 'PT_qbid_taxinc_thd', | ||
| 'ALD_BusinessLosses_c', | ||
| 'STD', 'II_em', 'II_em_ps', | ||
| 'AMT_em', 'AMT_em_ps', 'AMT_em_pe', | ||
| 'ID_ps', 'ID_AllTaxes_c'] | ||
|
|
||
| # specify current-law policy that includes TCJA inflation indexing rules | ||
| clp = Policy() | ||
| pdata = clp._vals | ||
| # calculate the inflation factor used to calculate the | ||
| # inflation-adjusted 2026 parameter values | ||
| final_ifactor = 1.0 | ||
| pyear = 2017 # prior year before TCJA first implemented | ||
| fyear = 2026 # final year in which parameter values revert to | ||
| # pre-TCJA values | ||
| # construct final-year inflation factor from prior year | ||
| # NOTE: pvalue[t+1] = pvalue[t] * ( 1 + irate[t] ) | ||
| for year in range(pyear, fyear): | ||
| final_ifactor *= 1 + \ | ||
| params._inflation_rates[year - params.start_year] | ||
|
|
||
| # identify policy parameters that have their values reverted in final year | ||
| skip_list = ['_II_brk7', '_PT_brk7'] # because they are both "infinity" (9e99) | ||
| fyr = fyear | ||
| reverting_params = list() | ||
| for pname in sorted(pdata.keys()): | ||
| pdict = pdata[pname] | ||
| if pdata[pname]['indexed'] and fyr in pdata[pname]['value_yrs']: | ||
| if pname not in skip_list: | ||
| reverting_params.append(pname) | ||
| print('number_of_reverting_parameters= {}'.format(len(reverting_params))) | ||
| long_param_vals = defaultdict(list) | ||
|
|
||
| # write ppp.old containing existing values for reverting policy parameters | ||
| old = open('ppp.old', 'w') | ||
| for pname in reverting_params: | ||
| old.write('*** {} ***\n'.format(pname)) | ||
| # write parameter values for each year in [pyear,fyear] range | ||
| for year in range(pyear, fyear + 1): | ||
| value = pdata[pname]['value'][year - syear] | ||
| old.write('{}: {}\n'.format(year, value)) | ||
| old.close() | ||
| for param in long_params: | ||
| vos = params.select_eq(param, year=pyear) | ||
| # use final_ifactor to inflate from 2017 to 2026 | ||
| for vo in vos: | ||
| long_param_vals[param].append( | ||
| # Create new dict to avoid modifying the original | ||
| dict( | ||
| vo, | ||
| value=min(9e99, round( | ||
| vo["value"] * final_ifactor, 0)), | ||
| year=fyear, | ||
| ) | ||
| ) | ||
|
|
||
| # get TCJA parameter inflation rates for each year | ||
| irate = clp.inflation_rates() | ||
| # call adjust method for new 2026 values | ||
| params.adjust(long_param_vals) | ||
| params.clear_state() | ||
| param_data = params.specification( | ||
| meta_data=False, serializable=True, use_state=False, _auto=False) | ||
|
|
||
| # construct final-year inflation factor from prior year | ||
| # < NOTE: pvalue[t+1] = pvalue[t] * ( 1 + irate[t] ) > | ||
| final_ifactor = 1.0 | ||
| for year in range(pyear, fyear): | ||
| final_ifactor *= 1 + irate[year - syear] | ||
| # read existing policy_current_law.json | ||
| with open('taxcalc/policy_current_law.json', 'r') as f: | ||
| pcl = json.load(f) | ||
|
|
||
| # construct intermediate-year inflation factors from base year | ||
| # < NOTE: pvalue[t+1] = pvalue[t] * ( 1 + irate[t] ) > | ||
| ifactor = dict() | ||
| factor = 1.0 | ||
| for year in range(byear, fyear): | ||
| ifactor[year] = factor | ||
| factor *= 1 + irate[year - syear] | ||
| # replace 2026 values in policy_current_law.json | ||
| for param in param_data: | ||
| pcl[param]["value"] = param_data[param] | ||
|
|
||
| # write or calculate policy parameter values for pyear through fyear | ||
| new = open('ppp.new', 'w') | ||
| for pname in reverting_params: | ||
| new.write('*** {} ***\n'.format(pname)) | ||
| # write parameter values for prior year | ||
| value = pdata[pname]['value'][pyear - syear] | ||
| new.write('{}: {}\n'.format(pyear, value)) | ||
| # write parameter values for year after prior year up through base year | ||
| for year in range(pyear + 1, byear + 1): | ||
| value = pdata[pname]['value'][year - syear] | ||
| new.write('{}: {}\n'.format(year, value)) | ||
| # compute parameter values for intermediate years | ||
| bvalue = pdata[pname]['value'][byear - syear] | ||
| for year in range(byear + 1, fyear): | ||
| if isinstance(bvalue, list): | ||
| value = list() | ||
| for idx in range(0, len(bvalue)): | ||
| val = min(9e99, round(bvalue[idx] * ifactor[year], 2)) | ||
| value.append(val) | ||
| else: | ||
| value = min(9e99, round(bvalue * ifactor[year], 2)) | ||
| new.write('{}: {}\n'.format(year, value)) | ||
| # compute final year parameter value | ||
| pvalue = pdata[pname]['value'][pyear - syear] | ||
| if isinstance(pvalue, list): | ||
| value = list() | ||
| for idx in range(0, len(pvalue)): | ||
| val = min(9e99, round(pvalue[idx] * final_ifactor, 0)) | ||
| value.append(val) | ||
| else: | ||
| value = min(9e99, round(pvalue * final_ifactor, 0)) | ||
| new.write('{}: {}\n'.format(fyear, value)) | ||
| new.close() | ||
| # write new policy_current_law.json | ||
| with open('taxcalc/policy_current_law.json', 'w') as pcl_old: | ||
| json.dump(pcl, pcl_old, indent=4) |
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