diff --git a/GEODE/Visualisation/ConfusionMatrix.py b/GEODE/Visualisation/ConfusionMatrix.py
index 47cec22426a7f584b48e11813881e33448e403e5..1a608af457a5d484752139406a2c40d5cbb16cef 100644
--- a/GEODE/Visualisation/ConfusionMatrix.py
+++ b/GEODE/Visualisation/ConfusionMatrix.py
@@ -57,8 +57,8 @@ def getArgs(arguments):
     cli.add_argument('inputFile')
     cli.add_argument('outputJSON')
     add_labels_argument(cli)
-    cli.add_argument('-m', '--maximal',
-                     action='store_const', const=True, default=False)
+    cli.add_argument('-m', '--maximal', action='store_const', const=True,
+                     default=False, help="Simplify the matrix into an MCM")
     return cli.parse_args(arguments)
 
 def extractConfusionMatrixCLI(arguments):