diff --git a/src/SIL.Machine/QualityEstimation/ChrF3QualityEstimator.cs b/src/SIL.Machine/QualityEstimation/ChrF3QualityEstimator.cs
index 1d8e34a26..933c8d5f7 100644
--- a/src/SIL.Machine/QualityEstimation/ChrF3QualityEstimator.cs
+++ b/src/SIL.Machine/QualityEstimation/ChrF3QualityEstimator.cs
@@ -9,8 +9,14 @@ namespace SIL.Machine.QualityEstimation
     /// <summary>
     /// Provides chrF3 quality estimation for pre-translations.
     /// </summary>
+    /// <remarks>
+    /// The usability score thresholds used are: Green 0.776; Yellow 0.681.
+    /// These correspond to chrF3 thresholds of: Green 53.0; Yellow 44.5.
+    /// </remarks>
     public class ChrF3QualityEstimator
     {
+        private const double GreenThreshold = 0.776;
+        private const double YellowThreshold = 0.681;
         private readonly double _intercept;
         private readonly double _slope;
 
@@ -28,19 +34,20 @@ public ChrF3QualityEstimator(double slope, double intercept)
         /// <summary>
         /// The threshold values used to calculate the usability label for every book or text.
         /// </summary>
-        public Thresholds BookThresholds { get; set; } = new Thresholds(greenThreshold: 0.745, yellowThreshold: 0.62);
+        public Thresholds BookThresholds { get; set; } =
+            new Thresholds(greenThreshold: GreenThreshold, yellowThreshold: YellowThreshold);
 
         /// <summary>
         /// The threshold values used to calculate the usability label for every chapter.
         /// </summary>
         public Thresholds ChapterThresholds { get; set; } =
-            new Thresholds(greenThreshold: 0.745, yellowThreshold: 0.62);
+            new Thresholds(greenThreshold: GreenThreshold, yellowThreshold: YellowThreshold);
 
         /// <summary>
         /// The threshold values used to calculate the usability label for every segment.
         /// </summary>
         public Thresholds SegmentThresholds { get; set; } =
-            new Thresholds(greenThreshold: 0.745, yellowThreshold: 0.62);
+            new Thresholds(greenThreshold: GreenThreshold, yellowThreshold: YellowThreshold);
 
         /// <summary>
         /// The usable parameters to calculate the usable probabilities.
diff --git a/tests/SIL.Machine.Tests/QualityEstimation/ChrF3QualityEstimatorTests.cs b/tests/SIL.Machine.Tests/QualityEstimation/ChrF3QualityEstimatorTests.cs
index 9c018f994..a73ccb5f5 100644
--- a/tests/SIL.Machine.Tests/QualityEstimation/ChrF3QualityEstimatorTests.cs
+++ b/tests/SIL.Machine.Tests/QualityEstimation/ChrF3QualityEstimatorTests.cs
@@ -13,7 +13,7 @@ public void ChrF3QualityEstimator_TxtFiles()
         var qualityEstimation = new ChrF3QualityEstimator(slope: 109.6145, intercept: -14.0633);
         List<(MultiKeyRef key, double confidence)> confidences =
         [
-            (new MultiKeyRef("MAT.txt", 1), 0.6020749899712906),
+            (new MultiKeyRef("MAT.txt", 1), 0.6220749899712906),
             (new MultiKeyRef("MAT.txt", 2), 0.5416165991875662),
             (new MultiKeyRef("MRK.txt", 1), 0.40324150219671917),
         ];
@@ -23,8 +23,8 @@ public void ChrF3QualityEstimator_TxtFiles()
         {
             Assert.That(usabilityTextSegments, Has.Count.EqualTo(3));
             Assert.That(usabilityTextSegments[0].Label, Is.EqualTo(UsabilityLabel.Green));
-            Assert.That(usabilityTextSegments[0].ProjectedChrF3, Is.EqualTo(51.93).Within(0.01));
-            Assert.That(usabilityTextSegments[0].Usability, Is.EqualTo(0.765).Within(0.001));
+            Assert.That(usabilityTextSegments[0].ProjectedChrF3, Is.EqualTo(54.12).Within(0.01));
+            Assert.That(usabilityTextSegments[0].Usability, Is.EqualTo(0.786).Within(0.001));
             Assert.That(usabilityTextSegments[0].Confidence, Is.EqualTo(confidences[0].confidence).Within(0.001));
             Assert.That(usabilityTextSegments[1].Label, Is.EqualTo(UsabilityLabel.Yellow));
             Assert.That(usabilityTextSegments[1].ProjectedChrF3, Is.EqualTo(45.31).Within(0.01));
@@ -36,9 +36,9 @@ public void ChrF3QualityEstimator_TxtFiles()
             Assert.That(usabilityTextSegments[2].Confidence, Is.EqualTo(confidences[2].confidence).Within(0.001));
             Assert.That(usabilityTexts, Has.Count.EqualTo(2));
             Assert.That(usabilityTexts[0].Label, Is.EqualTo(UsabilityLabel.Yellow));
-            Assert.That(usabilityTexts[0].ProjectedChrF3, Is.EqualTo(48.53).Within(0.01));
-            Assert.That(usabilityTexts[0].Usability, Is.EqualTo(0.728).Within(0.001));
-            Assert.That(usabilityTexts[0].Confidence, Is.EqualTo(0.571).Within(0.001));
+            Assert.That(usabilityTexts[0].ProjectedChrF3, Is.EqualTo(49.56).Within(0.01));
+            Assert.That(usabilityTexts[0].Usability, Is.EqualTo(0.738).Within(0.001));
+            Assert.That(usabilityTexts[0].Confidence, Is.EqualTo(0.580).Within(0.001));
             Assert.That(usabilityTexts[1].Label, Is.EqualTo(UsabilityLabel.Red));
             Assert.That(usabilityTexts[1].ProjectedChrF3, Is.EqualTo(30.14).Within(0.01));
             Assert.That(usabilityTexts[1].Usability, Is.EqualTo(0.465).Within(0.001));
@@ -52,7 +52,7 @@ public void ChrF3QualityEstimator_Verses()
         var qualityEstimation = new ChrF3QualityEstimator(slope: 109.6145, intercept: -14.0633);
         List<(ScriptureRef key, double confidence)> confidences =
         [
-            (new ScriptureRef(new VerseRef(1, 1, 1)), 0.6020749899712906),
+            (new ScriptureRef(new VerseRef(1, 1, 1)), 0.6220749899712906),
             (new ScriptureRef(new VerseRef(1, 1, 2)), 0.5416165991875662),
             (new ScriptureRef(new VerseRef(1, 2, 1)), 0.40324150219671917),
         ];
@@ -65,8 +65,8 @@ List<ScriptureBookUsability> usabilityBooks
         {
             Assert.That(usabilitySegments, Has.Count.EqualTo(3));
             Assert.That(usabilitySegments[0].Label, Is.EqualTo(UsabilityLabel.Green));
-            Assert.That(usabilitySegments[0].ProjectedChrF3, Is.EqualTo(51.93).Within(0.01));
-            Assert.That(usabilitySegments[0].Usability, Is.EqualTo(0.765).Within(0.001));
+            Assert.That(usabilitySegments[0].ProjectedChrF3, Is.EqualTo(54.12).Within(0.01));
+            Assert.That(usabilitySegments[0].Usability, Is.EqualTo(0.786).Within(0.001));
             Assert.That(usabilitySegments[0].Confidence, Is.EqualTo(confidences[0].confidence).Within(0.001));
             Assert.That(usabilitySegments[1].Label, Is.EqualTo(UsabilityLabel.Yellow));
             Assert.That(usabilitySegments[1].ProjectedChrF3, Is.EqualTo(45.31).Within(0.01));
@@ -78,18 +78,18 @@ List<ScriptureBookUsability> usabilityBooks
             Assert.That(usabilitySegments[2].Confidence, Is.EqualTo(confidences[2].confidence).Within(0.001));
             Assert.That(usabilityChapters, Has.Count.EqualTo(2));
             Assert.That(usabilityChapters[0].Label, Is.EqualTo(UsabilityLabel.Yellow));
-            Assert.That(usabilityChapters[0].ProjectedChrF3, Is.EqualTo(48.53).Within(0.01));
-            Assert.That(usabilityChapters[0].Usability, Is.EqualTo(0.728).Within(0.001));
-            Assert.That(usabilityChapters[0].Confidence, Is.EqualTo(0.571).Within(0.001));
+            Assert.That(usabilityChapters[0].ProjectedChrF3, Is.EqualTo(49.56).Within(0.01));
+            Assert.That(usabilityChapters[0].Usability, Is.EqualTo(0.738).Within(0.001));
+            Assert.That(usabilityChapters[0].Confidence, Is.EqualTo(0.580).Within(0.001));
             Assert.That(usabilityChapters[1].Label, Is.EqualTo(UsabilityLabel.Red));
             Assert.That(usabilityChapters[1].ProjectedChrF3, Is.EqualTo(30.14).Within(0.01));
             Assert.That(usabilityChapters[1].Usability, Is.EqualTo(0.465).Within(0.001));
             Assert.That(usabilityChapters[1].Confidence, Is.EqualTo(confidences[2].confidence).Within(0.001));
             Assert.That(usabilityBooks, Has.Count.EqualTo(1));
-            Assert.That(usabilityBooks[0].Label, Is.EqualTo(UsabilityLabel.Yellow));
-            Assert.That(usabilityBooks[0].ProjectedChrF3, Is.EqualTo(41.68).Within(0.01));
-            Assert.That(usabilityBooks[0].Usability, Is.EqualTo(0.640).Within(0.001));
-            Assert.That(usabilityBooks[0].Confidence, Is.EqualTo(0.508).Within(0.001));
+            Assert.That(usabilityBooks[0].Label, Is.EqualTo(UsabilityLabel.Red));
+            Assert.That(usabilityBooks[0].ProjectedChrF3, Is.EqualTo(42.28).Within(0.01));
+            Assert.That(usabilityBooks[0].Usability, Is.EqualTo(0.647).Within(0.001));
+            Assert.That(usabilityBooks[0].Confidence, Is.EqualTo(0.514).Within(0.001));
         }
     }
 }