From 78aa7432b232b61e67b45212da147a0606e4ae98 Mon Sep 17 00:00:00 2001
From: GHX5T-SOL <200635707+GHX5T-SOL@users.noreply.github.com>
Date: Tue, 19 May 2026 17:42:56 +0200
Subject: [PATCH] fix: clarify output plot unit labels

---
 ogcore/output_plots.py     | 28 +++++++++++++++++------
 tests/test_output_plots.py | 46 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 7 deletions(-)

diff --git a/ogcore/output_plots.py b/ogcore/output_plots.py
index d3bc2836b..7877d80d6 100644
--- a/ogcore/output_plots.py
+++ b/ogcore/output_plots.py
@@ -12,6 +12,9 @@
 from ogcore.utils import Inequality
 
 
+INTEREST_RATE_VARS = {"r_gov", "r", "r_p"}
+
+
 def plot_aggregates(
     base_tpi,
     base_params,
@@ -41,7 +44,8 @@ def plot_aggregates(
         var_list (list): names of variable to plot
         plot_type (string): type of plot, can be:
             'pct_diff': plots percentage difference between baseline
-                and reform ((reform-base)/base)
+                and reform ((reform-base)/base). For interest rates,
+                percentage point differences are plotted.
             'diff': plots difference between baseline and reform
                 (reform-base)
             'levels': plot variables in model units
@@ -73,6 +77,8 @@ def plot_aggregates(
     # Check that reform included if doing pct_diff or diff plot
     if plot_type == "pct_diff" or plot_type == "diff":
         assert reform_tpi is not None
+    only_interest_rates = all(v in INTEREST_RATE_VARS for v in var_list)
+    has_interest_rates = any(v in INTEREST_RATE_VARS for v in var_list)
     fig1, ax1 = plt.subplots()
     if not stationarized:
         for v in var_list:
@@ -91,7 +97,12 @@ def plot_aggregates(
                 plot_var = reform_tpi[v] - base_tpi[v]
             else:
                 plot_var = (reform_tpi[v] - base_tpi[v]) / base_tpi[v]
-            ylabel = r"Pct. change"
+            if only_interest_rates:
+                ylabel = r"Percentage point change"
+            elif has_interest_rates:
+                ylabel = r"Pct. or percentage point change"
+            else:
+                ylabel = r"Pct. change"
             plt.plot(
                 year_vec,
                 plot_var[start_index : start_index + num_years_to_plot],
@@ -119,7 +130,7 @@ def plot_aggregates(
                     ],
                     label="Reform " + VAR_LABELS[v],
                 )
-            ylabel = r"Model Units"
+            ylabel = r"Rate" if only_interest_rates else r"Model Units"
         elif plot_type == "forecast":
             # Need reform and baseline to ensure plot makes sense
             assert reform_tpi is not None
@@ -437,8 +448,8 @@ def plot_gdp_ratio(
         p (OG-Core Specifications class): parameters object
         var_list (list): names of variable to plot
         plot_type (string): type of plot, can be:
-            'diff': plots difference between baseline and reform
-                (reform-base)
+            'diff' or 'pct_diff': plots percentage point difference
+                between baseline and reform ratios to GDP (reform-base)
             'levels': plot variables in model units
         num_years_to_plot (integer): number of years to include in plot
         start_year (integer): year to start plot
@@ -453,7 +464,7 @@ def plot_gdp_ratio(
     assert isinstance(start_year, (int, np.integer))
     assert isinstance(num_years_to_plot, int)
     assert num_years_to_plot <= base_params.T
-    if plot_type == "diff":
+    if plot_type != "levels":
         assert reform_tpi is not None
     # Make sure both runs cover same time period
     if reform_tpi:
@@ -510,7 +521,10 @@ def plot_gdp_ratio(
                 plot_var[start_index : start_index + num_years_to_plot],
                 label=ToGDP_LABELS[v],
             )
-    ylabel = r"Percent of GDP"
+    if plot_type == "levels":
+        ylabel = r"Percent of GDP"
+    else:
+        ylabel = r"Percentage points of GDP"
     # vertical markers at certain years
     if vertical_line_years:
         for yr in vertical_line_years:
diff --git a/tests/test_output_plots.py b/tests/test_output_plots.py
index 35c09e0b6..4be822ada 100644
--- a/tests/test_output_plots.py
+++ b/tests/test_output_plots.py
@@ -249,6 +249,38 @@ def test_plot_aggregates_not_a_type(tmpdir):
         )
 
 
+def test_plot_aggregates_interest_rate_pct_diff_label():
+    fig = output_plots.plot_aggregates(
+        base_tpi,
+        base_params,
+        reform_tpi=reform_tpi,
+        reform_params=reform_params,
+        var_list=["r"],
+        plot_type="pct_diff",
+        num_years_to_plot=20,
+        start_year=int(base_params.start_year),
+    )
+
+    assert fig.axes[0].get_ylabel() == "Percentage point change"
+    plt.close()
+
+
+def test_plot_aggregates_interest_rate_levels_label():
+    fig = output_plots.plot_aggregates(
+        base_tpi,
+        base_params,
+        reform_tpi=reform_tpi,
+        reform_params=reform_params,
+        var_list=["r"],
+        plot_type="levels",
+        num_years_to_plot=20,
+        start_year=int(base_params.start_year),
+    )
+
+    assert fig.axes[0].get_ylabel() == "Rate"
+    plt.close()
+
+
 test_data = [
     (base_tpi, base_params, None, None, None, None, "levels"),
     (base_tpi, base_params, reform_tpi, reform_params, None, None, "levels"),
@@ -316,6 +348,20 @@ def test_plot_gdp_ratio_save_fig(tmpdir):
     assert isinstance(img, np.ndarray)
 
 
+def test_plot_gdp_ratio_pct_diff_label():
+    fig = output_plots.plot_gdp_ratio(
+        base_tpi,
+        base_params,
+        reform_tpi=reform_tpi,
+        reform_params=reform_params,
+        start_year=int(base_params.start_year),
+        plot_type="pct_diff",
+    )
+
+    assert fig.axes[0].get_ylabel() == "Percentage points of GDP"
+    plt.close()
+
+
 def test_ability_bar():
     fig = output_plots.ability_bar(
         base_tpi,