diff --git a/changelog.d/fix-ordinary-calendar-year-sampling.fixed.md b/changelog.d/fix-ordinary-calendar-year-sampling.fixed.md
new file mode 100644
index 0000000000..e45d745454
--- /dev/null
+++ b/changelog.d/fix-ordinary-calendar-year-sampling.fixed.md
@@ -0,0 +1 @@
+Fixed test_ordinary_parameters_read_every_key_as_before, which drew some of its ordinary parameters from the household energy price indices, a calendar-year series.
diff --git a/policyengine_uk/tests/test_process_time_reforms.py b/policyengine_uk/tests/test_process_time_reforms.py
index d67fa29932..0255b27b9c 100644
--- a/policyengine_uk/tests/test_process_time_reforms.py
+++ b/policyengine_uk/tests/test_process_time_reforms.py
@@ -57,6 +57,8 @@
 LAGGED_CPI = f"{GROWTH}.obr.lagged_cpi"
 INDICES = "gov.economic_assumptions.indices"
 ENERGY_PRICES = "gov.economic_assumptions.energy_prices"
+# The calendar-year series on the gov tree (invariant 2).
+CALENDAR_YEAR_SERIES = (f"{GROWTH}.", f"{INDICES}.", f"{ENERGY_PRICES}.")
 CPI_INDEX = f"{INDICES}.obr.consumer_price_index"
 INPUTS = "gov.economic_assumptions.statutory_uprating_inputs"
 AWE = f"{INPUTS}.awe_total_pay_may_july"
@@ -324,9 +326,7 @@ def test_calendar_year_series_are_the_growth_rates_indices_and_household_tree():
     for path in paths:
         if path.startswith("baseline."):
             continue
-        expected = path.startswith(
-            (f"{GROWTH}.", f"{INDICES}.", f"{ENERGY_PRICES}.", "household.")
-        )
+        expected = path.startswith(CALENDAR_YEAR_SERIES + ("household.",))
         assert reads(path) is expected, path
     assert not reads("gov.not.a.parameter")
 
@@ -600,8 +600,7 @@ def statutory_leaves():
 ORDINARY = [
     path
     for path in statutory_leaves()
-    if path.startswith("gov.")
-    and not path.startswith(("gov.economic_assumptions.yoy_growth.",))
+    if path.startswith("gov.") and not path.startswith(CALENDAR_YEAR_SERIES)
 ]
 KEYS = st.one_of(
     st.integers(2016, 2040),
@@ -613,6 +612,12 @@ def statutory_leaves():
 )
 
 
+def test_no_ordinary_parameter_reads_calendar_years():
+    reads = tbs_module.parameter_reads_calendar_years()
+    assert ORDINARY
+    assert [path for path in ORDINARY if reads(path)] == []
+
+
 @settings(max_examples=200, deadline=None, derandomize=True)
 @given(path=st.sampled_from(ORDINARY), key=KEYS)
 def test_ordinary_parameters_read_every_key_as_before(path, key):