diff --git a/src/edr_pydantic/parameter.py b/src/edr_pydantic/parameter.py
index c2a31f7..8102c59 100644
--- a/src/edr_pydantic/parameter.py
+++ b/src/edr_pydantic/parameter.py
@@ -15,9 +15,7 @@
 class MeasurementType(EdrBaseModel):
     method: str
     # TODO: Add validation of ISO 8601 duration (including leading minus sign)
-    # TODO: Confusion in spec on the field name, duration versus period.
-    #  See https://github.com/opengeospatial/ogcapi-environmental-data-retrieval/issues/560
-    period: str
+    duration: str
 
 
 class Parameter(EdrBaseModel, extra="allow"):
diff --git a/tests/test_data/doc-example-collections.json b/tests/test_data/doc-example-collections.json
index 2864abb..fee708e 100644
--- a/tests/test_data/doc-example-collections.json
+++ b/tests/test_data/doc-example-collections.json
@@ -198,7 +198,7 @@
                     },
                     "measurementType": {
                         "method": "mean",
-                        "period": "-PT10M/PT0M"
+                        "duration": "-PT10M"
                     }
                 },
                 "Wind Speed": {
@@ -217,7 +217,7 @@
                     },
                     "measurementType": {
                         "method": "mean",
-                        "period": "-PT10M/PT0M"
+                        "duration": "-PT10M"
                     }
                 },
                 "Wind Gust": {
@@ -236,7 +236,7 @@
                     },
                     "measurementType": {
                         "method": "maximum",
-                        "period": "-PT10M/PT0M"
+                        "duration": "-PT10M"
                     }
                 },
                 "Air Temperature": {
@@ -255,7 +255,7 @@
                     },
                     "measurementType": {
                         "method": "instantaneous",
-                        "period": "PT0M"
+                        "duration": "PT0M"
                     }
                 },
                 "Weather": {
@@ -274,7 +274,7 @@
                     },
                     "measurementType": {
                         "method": "instantaneous",
-                        "period": "PT0M"
+                        "duration": "PT0M"
                     }
                 },
                 "Relative Humidity": {
@@ -293,7 +293,7 @@
                     },
                     "measurementType": {
                         "method": "instantaneous",
-                        "period": "PT0M"
+                        "duration": "PT0M"
                     }
                 },
                 "Dew point": {
@@ -312,7 +312,7 @@
                     },
                     "measurementType": {
                         "method": "instantaneous",
-                        "period": "PT0M"
+                        "duration": "PT0M"
                     }
                 },
                 "Pressure": {
@@ -331,7 +331,7 @@
                     },
                     "measurementType": {
                         "method": "instantaneous",
-                        "period": "PT0M"
+                        "duration": "PT0M"
                     }
                 },
                 "Pressure Tendancy": {
@@ -350,7 +350,7 @@
                     },
                     "measurementType": {
                         "method": "instantaneous",
-                        "period": "PT0M"
+                        "duration": "PT0M"
                     }
                 },
                 "Visibility": {
@@ -369,7 +369,7 @@
                     },
                     "measurementType": {
                         "method": "instantaneous",
-                        "period": "PT0M"
+                        "duration": "PT0M"
                     }
                 }
             }
@@ -539,7 +539,7 @@
                     },
                     "measurementType": {
                         "method": "mean",
-                        "period": "-PT10M/PT0M"
+                        "duration": "-PT10M"
                     }
                 },
                 "Wind Speed": {
@@ -558,7 +558,7 @@
                     },
                     "measurementType": {
                         "method": "mean",
-                        "period": "-PT10M/PT0M"
+                        "duration": "-PT10M"
                     }
                 },
                 "Wind Gust": {
@@ -577,7 +577,7 @@
                     },
                     "measurementType": {
                         "method": "maximum",
-                        "period": "-PT10M/PT0M"
+                        "duration": "-PT10M"
                     }
                 },
                 "Air Temperature": {
@@ -596,7 +596,7 @@
                     },
                     "measurementType": {
                         "method": "instantaneous",
-                        "period": "PT0M"
+                        "duration": "PT0M"
                     }
                 },
                 "Weather": {
@@ -615,7 +615,7 @@
                     },
                     "measurementType": {
                         "method": "instantaneous",
-                        "period": "PT0M"
+                        "duration": "PT0M"
                     }
                 },
                 "Relative Humidity": {
@@ -634,7 +634,7 @@
                     },
                     "measurementType": {
                         "method": "instantaneous",
-                        "period": "PT0M"
+                        "duration": "PT0M"
                     }
                 },
                 "Feels like temperature": {
@@ -653,7 +653,7 @@
                     },
                     "measurementType": {
                         "method": "instantaneous",
-                        "period": "PT0M"
+                        "duration": "PT0M"
                     }
                 },
                 "UV index": {
@@ -672,7 +672,7 @@
                     },
                     "measurementType": {
                         "method": "instantaneous",
-                        "period": "PT0M"
+                        "duration": "PT0M"
                     }
                 },
                 "Probability of precipitation": {
@@ -691,7 +691,7 @@
                     },
                     "measurementType": {
                         "method": "instantaneous",
-                        "period": "PT0M"
+                        "duration": "PT0M"
                     }
                 },
                 "Visibility": {
@@ -710,7 +710,7 @@
                     },
                     "measurementType": {
                         "method": "instantaneous",
-                        "period": "PT0M"
+                        "duration": "PT0M"
                     }
                 }
             }
diff --git a/tests/test_data/parameter-names.json b/tests/test_data/parameter-names.json
index 1583484..3ce8b0f 100644
--- a/tests/test_data/parameter-names.json
+++ b/tests/test_data/parameter-names.json
@@ -15,7 +15,7 @@
         },
         "measurementType": {
             "method": "instantaneous",
-            "period": "PT0S"
+            "duration": "PT0S"
         }
     },
     "u-component_of_wind_altitude_above_msl": {
@@ -34,7 +34,7 @@
         },
         "measurementType": {
             "method": "instantaneous",
-            "period": "PT0S"
+            "duration": "PT0S"
         }
     },
     "v-component_of_wind_altitude_above_msl": {
@@ -53,7 +53,7 @@
         },
         "measurementType": {
             "method": "instantaneous",
-            "period": "PT0S"
+            "duration": "PT0S"
         }
     }
 }
diff --git a/tests/test_data/parameter-with-extent.json b/tests/test_data/parameter-with-extent.json
index ad521ec..e247a9a 100644
--- a/tests/test_data/parameter-with-extent.json
+++ b/tests/test_data/parameter-with-extent.json
@@ -39,6 +39,6 @@
     },
     "measurementType": {
         "method": "instantaneous",
-        "period": "PT0S"
+        "duration": "PT0S"
     }
 }