diff --git a/metricflow/plan_conversion/dataflow_to_sql.py b/metricflow/plan_conversion/dataflow_to_sql.py
index 63592b54f7..ddb2024609 100644
--- a/metricflow/plan_conversion/dataflow_to_sql.py
+++ b/metricflow/plan_conversion/dataflow_to_sql.py
@@ -924,7 +924,10 @@ def visit_combine_aggregated_outputs_node(self, node: CombineAggregatedOutputsNo
         linkable_specs = from_data_set.data_set.instance_set.spec_set.linkable_specs
         assert all(
             [set(x.data_set.instance_set.spec_set.linkable_specs) == set(linkable_specs) for x in join_data_sets]
-        ), "All parent nodes should have the same set of linkable instances since all values are coalesced."
+        ), (
+            "All join data sets should have the same set of linkable instances as the from dataset since all values are coalesced. "
+            f"Got from dataset: {from_data_set}\nGot join datasets: {join_data_sets}"
+        )
 
         linkable_spec_set = from_data_set.data_set.instance_set.spec_set.transform(SelectOnlyLinkableSpecs())
         join_type = SqlJoinType.CROSS_JOIN if len(linkable_spec_set.all_specs) == 0 else SqlJoinType.FULL_OUTER