diff --git a/rre-core/src/main/java/io/sease/rre/core/domain/metrics/ParameterizedMetricClassManager.java b/rre-core/src/main/java/io/sease/rre/core/domain/metrics/ParameterizedMetricClassManager.java
index 7e6271d5..c12b73a9 100644
--- a/rre-core/src/main/java/io/sease/rre/core/domain/metrics/ParameterizedMetricClassManager.java
+++ b/rre-core/src/main/java/io/sease/rre/core/domain/metrics/ParameterizedMetricClassManager.java
@@ -22,6 +22,9 @@ public class ParameterizedMetricClassManager extends SimpleMetricClassManager im
     private final static Logger LOGGER = LogManager.getLogger(ParameterizedMetricClassManager.class);
 
     public static final String NAME_KEY = "name";
+    public static final String MAXIMUM_GRADE_KEY = "maximumGrade";
+    public static final String MISSING_GRADE_KEY = "missingGrade";
+
     private static final String METRIC_CLASS_KEY = "class";
 
     private final Map<String, Map<String, Object>> metricConfiguration;
diff --git a/rre-core/src/main/java/io/sease/rre/core/domain/metrics/impl/ExpectedReciprocalRank.java b/rre-core/src/main/java/io/sease/rre/core/domain/metrics/impl/ExpectedReciprocalRank.java
index dcc84840..40608b88 100644
--- a/rre-core/src/main/java/io/sease/rre/core/domain/metrics/impl/ExpectedReciprocalRank.java
+++ b/rre-core/src/main/java/io/sease/rre/core/domain/metrics/impl/ExpectedReciprocalRank.java
@@ -56,8 +56,8 @@ public class ExpectedReciprocalRank extends Metric {
      *                     or 2, depending whether or not {@code maxgrade} has been specified.
      * @param name         the name to use for this metric. If {@code null}, will default to {@code ERR@k}.
      */
-    public ExpectedReciprocalRank(@JsonProperty("maxgrade") final Float maxgrade,
-                                  @JsonProperty("defaultgrade") final Float defaultgrade,
+    public ExpectedReciprocalRank(@JsonProperty(ParameterizedMetricClassManager.MAXIMUM_GRADE_KEY) final Float maxgrade,
+                                  @JsonProperty(ParameterizedMetricClassManager.MISSING_GRADE_KEY) final Float defaultgrade,
                                   @JsonProperty("k") final int k,
                                   @JsonProperty(ParameterizedMetricClassManager.NAME_KEY) final String name) {
         super(Optional.ofNullable(name).orElse("ERR@" + k));
diff --git a/rre-core/src/main/java/io/sease/rre/core/domain/metrics/impl/NDCGAtK.java b/rre-core/src/main/java/io/sease/rre/core/domain/metrics/impl/NDCGAtK.java
index 6bba45fd..cef94a5d 100644
--- a/rre-core/src/main/java/io/sease/rre/core/domain/metrics/impl/NDCGAtK.java
+++ b/rre-core/src/main/java/io/sease/rre/core/domain/metrics/impl/NDCGAtK.java
@@ -72,8 +72,8 @@ public NDCGAtK(final int k) {
      * @param name         the name to use for this metric. If {@code null}, will default to {@code NDCG@k}.
      */
     public NDCGAtK(@JsonProperty("k") final int k,
-                   @JsonProperty("maxgrade") final Float maxgrade,
-                   @JsonProperty("defaultgrade") final Float defaultgrade,
+                   @JsonProperty(ParameterizedMetricClassManager.MAXIMUM_GRADE_KEY) final Float maxgrade,
+                   @JsonProperty(ParameterizedMetricClassManager.MISSING_GRADE_KEY) final Float defaultgrade,
                    @JsonProperty(ParameterizedMetricClassManager.NAME_KEY) final String name) {
         super(Optional.ofNullable(name).orElse("NDCG@" + k));
         if (maxgrade == null) {
diff --git a/rre-core/src/main/java/io/sease/rre/core/domain/metrics/impl/ReciprocalRank.java b/rre-core/src/main/java/io/sease/rre/core/domain/metrics/impl/ReciprocalRank.java
index 04a7928a..6253bd4d 100644
--- a/rre-core/src/main/java/io/sease/rre/core/domain/metrics/impl/ReciprocalRank.java
+++ b/rre-core/src/main/java/io/sease/rre/core/domain/metrics/impl/ReciprocalRank.java
@@ -60,8 +60,8 @@ public ReciprocalRank() {
      * @param name         the name to use for this metric. If {@code null}, will default to {@code RR@k}.
      */
     public ReciprocalRank(@JsonProperty("k") final int k,
-                          @JsonProperty("maxgrade") final Float maxgrade,
-                          @JsonProperty("defaultgrade") final Float defaultgrade,
+                          @JsonProperty(ParameterizedMetricClassManager.MAXIMUM_GRADE_KEY) final Float maxgrade,
+                          @JsonProperty(ParameterizedMetricClassManager.MISSING_GRADE_KEY) final Float defaultgrade,
                           @JsonProperty(ParameterizedMetricClassManager.NAME_KEY) final String name) {
         super(Optional.ofNullable(name).orElse("RR@" + k));
         this.k = k;