diff --git a/src/rad/resources/schemas/reference_files/distortion-1.0.0.yaml b/src/rad/resources/schemas/reference_files/distortion-1.0.0.yaml
index 24890cf2..22f51582 100644
--- a/src/rad/resources/schemas/reference_files/distortion-1.0.0.yaml
+++ b/src/rad/resources/schemas/reference_files/distortion-1.0.0.yaml
@@ -13,13 +13,17 @@ properties:
     allOf:
       - $ref: asdf://stsci.edu/datamodels/roman/schemas/reference_files/ref_common-1.0.0
       - type: object
+
+        input_units: "pixel"
+        output_units: "arcsec"
+
         properties:
           reftype:
             type: string
             enum: [DISTORTION]
       - $ref: asdf://stsci.edu/datamodels/roman/schemas/reference_files/ref_optical_element-1.0.0
   coordinate_distortion_transform:
-    title: Distortion Transform Model
+    title: Distortion Transform Model with inputs in "pixel" and outputs in "arcsec"
     description: |
       The astropy.modeling.Model instance of of the distortion transform model.
     type: object
diff --git a/src/rad/resources/schemas/reference_files/inverselinearity-1.0.0.yaml b/src/rad/resources/schemas/reference_files/inverselinearity-1.0.0.yaml
index a364deee..d6b7d908 100644
--- a/src/rad/resources/schemas/reference_files/inverselinearity-1.0.0.yaml
+++ b/src/rad/resources/schemas/reference_files/inverselinearity-1.0.0.yaml
@@ -13,6 +13,10 @@ properties:
     allOf:
       - $ref: asdf://stsci.edu/datamodels/roman/schemas/reference_files/ref_common-1.0.0
       - type: object
+
+        input_units: "DN"
+        output_units: "DN"
+
         properties:
           reftype:
             type: string
diff --git a/src/rad/resources/schemas/reference_files/linearity-1.0.0.yaml b/src/rad/resources/schemas/reference_files/linearity-1.0.0.yaml
index c11ee5df..8b56ceba 100644
--- a/src/rad/resources/schemas/reference_files/linearity-1.0.0.yaml
+++ b/src/rad/resources/schemas/reference_files/linearity-1.0.0.yaml
@@ -13,6 +13,10 @@ properties:
     allOf:
       - $ref: asdf://stsci.edu/datamodels/roman/schemas/reference_files/ref_common-1.0.0
       - type: object
+
+        input_units: "DN"
+        output_units: "DN"
+
         properties:
           reftype:
             type: string
diff --git a/src/rad/resources/schemas/reference_files/refpix-1.0.0.yaml b/src/rad/resources/schemas/reference_files/refpix-1.0.0.yaml
index 1a5dc672..ea2a14fb 100644
--- a/src/rad/resources/schemas/reference_files/refpix-1.0.0.yaml
+++ b/src/rad/resources/schemas/reference_files/refpix-1.0.0.yaml
@@ -15,6 +15,10 @@ properties:
     allOf:
       - $ref: asdf://stsci.edu/datamodels/roman/schemas/reference_files/ref_common-1.0.0
       - type: object
+
+        input_units: "DN"
+        output_units: "DN"
+
         properties:
           reftype:
             type: string