diff --git a/README.md b/README.md
index 2085de8..79e7236 100644
--- a/README.md
+++ b/README.md
@@ -56,7 +56,7 @@ Remember to replace `[version]` with [a deciles-charts version][4]:
 generate_deciles_charts:
   run: >
     deciles-charts:[version]
-      --input_dir output
+      --input-files output/measure_*.csv
       --output_dir output
   needs: [generate_measures]
   outputs:
diff --git a/analysis/deciles_charts.py b/analysis/deciles_charts.py
index e6916bb..85bc09c 100644
--- a/analysis/deciles_charts.py
+++ b/analysis/deciles_charts.py
@@ -1,4 +1,5 @@
 import argparse
+import glob
 import pathlib
 import re
 
@@ -17,18 +18,12 @@ def _get_group_by(measure_table):
     return list(measure_table.columns[:-4])
 
 
-def get_measure_tables(path):
-    if not path.is_dir():
-        raise AttributeError()
-
-    for sub_path in path.iterdir():
-        if not sub_path.is_file():
-            continue
-
-        measure_fname_match = re.match(MEASURE_FNAME_REGEX, sub_path.name)
+def get_measure_tables(input_files):
+    for input_file in input_files:
+        measure_fname_match = re.match(MEASURE_FNAME_REGEX, input_file.name)
         if measure_fname_match is not None:
             # The `date` column is assigned by the measures framework.
-            measure_table = pandas.read_csv(sub_path, parse_dates=["date"])
+            measure_table = pandas.read_csv(input_file, parse_dates=["date"])
 
             # We can reconstruct the parameters passed to `Measure` without
             # the study definition.
@@ -52,13 +47,21 @@ def write_deciles_chart(deciles_chart, path):
     deciles_chart.savefig(path)
 
 
+def get_path(*args):
+    return pathlib.Path(*args).resolve()
+
+
+def match_paths(pattern):
+    return [get_path(x) for x in glob.glob(pattern)]
+
+
 def parse_args():
     parser = argparse.ArgumentParser()
     parser.add_argument(
-        "--input-dir",
+        "--input-files",
         required=True,
-        type=pathlib.Path,
-        help="Path to the input directory",
+        type=match_paths,
+        help="Glob pattern for matching one or more input files",
     )
     parser.add_argument(
         "--output-dir",
@@ -71,10 +74,10 @@ def parse_args():
 
 def main():
     args = parse_args()
-    input_dir = args.input_dir
+    input_files = args.input_files
     output_dir = args.output_dir
 
-    for measure_table in get_measure_tables(input_dir):
+    for measure_table in get_measure_tables(input_files):
         measure_table = drop_zero_denominator_rows(measure_table)
         chart = get_deciles_chart(measure_table)
         id_ = measure_table.attrs["id"]
diff --git a/project.yaml b/project.yaml
index 3add6ba..2d24814 100644
--- a/project.yaml
+++ b/project.yaml
@@ -27,7 +27,7 @@ actions:
   generate_deciles_charts:
     run: >
       python:latest analysis/deciles_charts.py
-        --input-dir output
+        --input-files output/measure_*.csv
         --output-dir output
     needs: [generate_measures]
     outputs:
diff --git a/tests/test_deciles_charts.py b/tests/test_deciles_charts.py
index de9413b..a32af5f 100644
--- a/tests/test_deciles_charts.py
+++ b/tests/test_deciles_charts.py
@@ -8,23 +8,11 @@
 
 
 class TestGetMeasureTables:
-    def test_path_is_not_dir(self, tmp_path):
-        tmp_file = tmp_path / "measure_sbp_by_practice.csv"
-        tmp_file.touch()
-        with pytest.raises(AttributeError):
-            next(deciles_charts.get_measure_tables(tmp_file))
-
-    def test_no_recurse(self, tmp_path):
-        tmp_sub_path = tmp_path / "measures"
-        tmp_sub_path.mkdir()
-        with pytest.raises(StopIteration):
-            next(deciles_charts.get_measure_tables(tmp_path))
-
     def test_input_table(self, tmp_path):
         tmp_file = tmp_path / "input_2019-01-01.csv"
         tmp_file.touch()
         with pytest.raises(StopIteration):
-            next(deciles_charts.get_measure_tables(tmp_path))
+            next(deciles_charts.get_measure_tables([tmp_path]))
 
     def test_measure_table(self, tmp_path):
         # arrange
@@ -38,10 +26,11 @@ def test_measure_table(self, tmp_path):
             }
         )
         measure_table_in["date"] = pandas.to_datetime(measure_table_in["date"])
-        measure_table_in.to_csv(tmp_path / "measure_sbp_by_practice.csv", index=False)
+        input_file = tmp_path / "measure_sbp_by_practice.csv"
+        measure_table_in.to_csv(input_file, index=False)
 
         # act
-        measure_table_out = next(deciles_charts.get_measure_tables(tmp_path))
+        measure_table_out = next(deciles_charts.get_measure_tables([input_file]))
 
         # assert
         testing.assert_frame_equal(measure_table_out, measure_table_in)
@@ -90,18 +79,35 @@ def test_parse_args(tmp_path, monkeypatch):
         "sys.argv",
         [
             "deciles_charts.py",
-            "--input-dir",
-            "input",
+            "--input-files",
+            "input/measure_*.csv",
             "--output-dir",
             "output",
         ],
     )
-    (tmp_path / "input").mkdir()
+
+    input_dir = tmp_path / "input"
+    input_dir.mkdir()
+
+    input_files = []
+    for input_file_name in [
+        "measure_has_sbp_event_by_stp_code.csv",
+        "measure_has_sbp_event_by_stp_code_2021-01-01.csv",
+        "measure_has_sbp_event_by_stp_code_2021-02-01.csv",
+        "measure_has_sbp_event_by_stp_code_2021-03-01.csv",
+        "measure_has_sbp_event_by_stp_code_2021-04-01.csv",
+        "measure_has_sbp_event_by_stp_code_2021-05-01.csv",
+        "measure_has_sbp_event_by_stp_code_2021-06-01.csv",
+    ]:
+        input_file = input_dir / input_file_name
+        input_file.touch()
+        input_files.append(input_file)
+
     (tmp_path / "output").mkdir()
 
     # act
     args = deciles_charts.parse_args()
 
     # assert
-    assert args.input_dir == pathlib.Path("input")
+    assert sorted(args.input_files) == sorted(input_files)
     assert args.output_dir == pathlib.Path("output")