diff --git a/linkage_dag.py b/linkage_dag.py
index 99fd773..1679db9 100644
--- a/linkage_dag.py
+++ b/linkage_dag.py
@@ -361,8 +361,8 @@
         task_id="import_id_mapping",
         bucket=bucket,
         source_objects=[f"{tmp_dir}/id_mapping.jsonl"],
-        schema_object=f"{schema_dir}/sources.json",
-        destination_project_dataset_table=f"{staging_dataset}.sources",
+        schema_object=f"{schema_dir}/id_mapping.json",
+        destination_project_dataset_table=f"{staging_dataset}.id_mapping",
         source_format="NEWLINE_DELIMITED_JSON",
         create_disposition="CREATE_IF_NEEDED",
         write_disposition="WRITE_TRUNCATE"
@@ -413,10 +413,12 @@
     staging_tables = ["sources", "references", all_metadata_table]
     production_tables = ["sources", "references"]
     for table_name in staging_tables:
+        compare_table_name = table_name if table_name != all_metadata_table else all_metadata_table+"_last_run"
+        compare_dataset = production_dataset if table_name != all_metadata_table else staging_dataset
         check_queries.append(BigQueryCheckOperator(
             task_id="check_monotonic_increase_"+table_name.lower(),
             sql=(f"select (select count(0) from {staging_dataset}.{table_name}) >= "
-                 f"(select 0.8*count(0) from {production_dataset}.{table_name})"),
+                 f"(select 0.8*count(0) from {compare_dataset}.{compare_table_name})"),
             use_legacy_sql=False
         ))
 
@@ -453,7 +455,7 @@
         ),
         BigQueryCheckOperator(
             task_id="no_null_references",
-            sql=f"select count(0) = 0 from {staging_dataset}.references where id is null or ref_id is null",
+            sql=f"select count(0) = 0 from {staging_dataset}.references where merged_id is null or ref_id is null",
             use_legacy_sql = False
         ),
         BigQueryCheckOperator(
diff --git a/schemas/id_mapping.json b/schemas/id_mapping.json
new file mode 100644
index 0000000..f1e4bef
--- /dev/null
+++ b/schemas/id_mapping.json
@@ -0,0 +1,14 @@
+[
+  {
+    "mode": "REQUIRED",
+    "name": "merged_id",
+    "type": "STRING",
+    "description": "CSET merged id of a set of articles judged to be the same"
+  },
+  {
+    "mode": "REQUIRED",
+    "name": "orig_id",
+    "type": "STRING",
+    "description": "Originating dataset's id for an article"
+  }
+]
\ No newline at end of file
diff --git a/schemas/sources.json b/schemas/sources.json
index caa4cab..7fb16d8 100644
--- a/schemas/sources.json
+++ b/schemas/sources.json
@@ -7,7 +7,7 @@
   },
   {
     "mode": "REQUIRED",
-    "name": "orig_ids",
+    "name": "orig_id",
     "type": "STRING",
     "description": "Originating dataset's id for an article"
   },
diff --git a/sql/sources.sql b/sql/sources.sql
index 5287ec1..9a4b1d3 100644
--- a/sql/sources.sql
+++ b/sql/sources.sql
@@ -3,7 +3,7 @@ select distinct
   a.merged_id,
   a.orig_id,
   b.dataset
-from {{staging_dataset}}.sources a
-left join
+from {{staging_dataset}}.id_mapping a
+inner join
 {{staging_dataset}}.union_metadata b
 on a.orig_id = b.id