Fix bad multiplication in uprating (#1260)

* Fix bad multiplication in uprating

* Update reform tests

Author: nikhilwoodruff

changelog_entry.yaml

@@ -0,0 +1,4 @@
+- bump: patch
+  changes:
+    fixed:
+    - Bug in uprating.

policyengine_uk/data/economic_assumptions.py

@@ -48,7 +48,9 @@ def apply_single_year_uprating(
                     prev_year_value = getattr(previous_year, table_name)[
                         variable
                     ]
-                    current_year_value = prev_year_value * index_rel_change
+                    current_year_value = prev_year_value * (
+                        1 + index_rel_change
+                    )
                     getattr(current_year, table_name)[
                         variable
                     ] = current_year_value
@@ -158,11 +160,6 @@ def uprate_rent(
         private_rent_growth = (
             aggregate_growth - social_weight * social_rent_growth
         ) / private_weight
-        print(
-            f"Backed out private rent growth: {private_rent_growth:.1%} in {year}"
-        )
-        print(f"OBR aggregate rent growth: {aggregate_growth:.1%} in {year}")
-        print(f"Social rent growth: {social_rent_growth:.1%} in {year}")
 
         current_year.household["rent"] = np.where(
             is_private_rented,
@@ -182,3 +179,6 @@ def reset_uprating(
     for year in dataset.datasets:
         if year != first_year:
             dataset.datasets[year] = dataset.datasets[first_year].copy()
+            dataset.datasets[year].time_period = str(year)
+
+    return dataset

policyengine_uk/tests/microsimulation/reforms_config.yaml

@@ -1,6 +1,6 @@
 reforms:
 - name: Raise basic rate by 1pp
-  expected_impact: 7.5
+  expected_impact: 7.6
   parameters:
     gov.hmrc.income_tax.rates.uk[0].rate: 0.21
 - name: Raise higher rate by 1pp
@@ -16,18 +16,18 @@ reforms:
   parameters:
     gov.hmrc.child_benefit.amount.additional: 25
 - name: Reduce Universal Credit taper rate to 20%
-  expected_impact: -36.4
+  expected_impact: -36.6
   parameters:
     gov.dwp.universal_credit.means_test.reduction_rate: 0.2
 - name: Raise Class 1 main employee NICs rate to 10%
   expected_impact: 12.3
   parameters:
     gov.hmrc.national_insurance.class_1.rates.employee.main: 0.1
 - name: Raise VAT standard rate by 2pp
-  expected_impact: 18.9
+  expected_impact: 18.8
   parameters:
     gov.hmrc.vat.standard_rate: 0.22
 - name: Raise additional rate by 3pp
-  expected_impact: 5.3
+  expected_impact: 5.4
   parameters:
     gov.hmrc.income_tax.rates.uk[2].rate: 0.48