Index: Ringtoets/Common/src/Ringtoets.Common.Service/ProbabilityAssessmentService.cs
===================================================================
diff -u -r678dc8c8dbb01fd889a082ae88c9f9d42f597a10 -r1957c54820f55f8de15e34add4577a78b2e96850
--- Ringtoets/Common/src/Ringtoets.Common.Service/ProbabilityAssessmentService.cs	(.../ProbabilityAssessmentService.cs)	(revision 678dc8c8dbb01fd889a082ae88c9f9d42f597a10)
+++ Ringtoets/Common/src/Ringtoets.Common.Service/ProbabilityAssessmentService.cs	(.../ProbabilityAssessmentService.cs)	(revision 1957c54820f55f8de15e34add4577a78b2e96850)
@@ -19,7 +19,6 @@
 // Stichting Deltares and remain full property of Stichting Deltares at all times.
 // All rights reserved.
 
-using System;
 using MathNet.Numerics.Distributions;
 using Ringtoets.Common.Data.Probability;
 
@@ -31,19 +30,16 @@
     public static class ProbabilityAssessmentService
     {
         /// <summary>
-        /// Calculates the <see cref="ProbabilityAssessmentOutput"/> given <paramref name="probabilityAssessmentInput"/> and <paramref name="reliability"/>.
+        /// Calculates <see cref="ProbabilityAssessmentOutput"/> based on the provided parameters.
         /// </summary>
-        /// <param name="probabilityAssessmentInput">The probability assesment input to use for the calculation.</param>
+        /// <param name="norm">The return period to assess for.</param>
+        /// <param name="contribution">The contribution of the failure mechanism as a percentage (0-100)
+        /// to the total of the failure probability of the assessment section.</param>
+        /// <param name="lengthEffectN">The 'N' parameter used to factor in the 'length effect'.</param>
         /// <param name="reliability">The reliability to use for the calculation.</param>
-        /// <exception cref="ArgumentNullException">Thrown when <paramref name="probabilityAssessmentInput"/> is <c>null</c>.</exception>
-        public static ProbabilityAssessmentOutput Calculate(ProbabilityAssessmentInput probabilityAssessmentInput, double reliability)
+        public static ProbabilityAssessmentOutput Calculate(double norm, double contribution, double lengthEffectN, double reliability)
         {
-            if (probabilityAssessmentInput == null)
-            {
-                throw new ArgumentNullException("probabilityAssessmentInput");
-            }
-
-            var requiredProbability = RequiredProbability(probabilityAssessmentInput.Contribution / 100.0, probabilityAssessmentInput.Norm, probabilityAssessmentInput.N);
+            var requiredProbability = RequiredProbability(contribution / 100.0, norm, lengthEffectN);
             var probability = ReliabilityToProbability(reliability);
             var requiredReliability = ProbabilityToReliability(requiredProbability);
             var factorOfSafety = FactorOfSafety(reliability, requiredReliability);
Index: Ringtoets/Common/test/Ringtoets.Common.Service.Test/ProbabilityAssessmentServiceTest.cs
===================================================================
diff -u -r678dc8c8dbb01fd889a082ae88c9f9d42f597a10 -r1957c54820f55f8de15e34add4577a78b2e96850
--- Ringtoets/Common/test/Ringtoets.Common.Service.Test/ProbabilityAssessmentServiceTest.cs	(.../ProbabilityAssessmentServiceTest.cs)	(revision 678dc8c8dbb01fd889a082ae88c9f9d42f597a10)
+++ Ringtoets/Common/test/Ringtoets.Common.Service.Test/ProbabilityAssessmentServiceTest.cs	(.../ProbabilityAssessmentServiceTest.cs)	(revision 1957c54820f55f8de15e34add4577a78b2e96850)
@@ -19,9 +19,7 @@
 // Stichting Deltares and remain full property of Stichting Deltares at all times.
 // All rights reserved.
 
-using System;
 using NUnit.Framework;
-using Ringtoets.Common.Data.Probability;
 using Ringtoets.Common.Data.TestUtil;
 
 namespace Ringtoets.Common.Service.Test
@@ -30,17 +28,6 @@
     public class ProbabilityAssessmentServiceTest
     {
         [Test]
-        public void Calculate_NullProbabilityAssessmentInput_ThrowsArgumentNullException()
-        {
-            //Call
-            TestDelegate test = () => ProbabilityAssessmentService.Calculate(null, double.NaN);
-
-            // Assert
-            var exception = Assert.Throws<ArgumentNullException>(test);
-            Assert.AreEqual("probabilityAssessmentInput", exception.ParamName);
-        }
-
-        [Test]
         [TestCase(30000, 100, 2, 60000)]
         [TestCase(30000, 100, 1, 30000)]
         [TestCase(30000, 24, 2, 250000)]
@@ -51,16 +38,8 @@
         [TestCase(20000, 24, 1, 83333.33)]
         public void RequiredProbability_DifferentInputs_ReturnsExpectedValue(int norm, double contribution, int lengthEffectN, double expectedResult)
         {
-            // Setup
-            var input = new ProbabilityAssessmentInput
-            {
-                Norm = norm,
-                Contribution = contribution,
-                N = lengthEffectN
-            };
-
             // Call
-            var probabilityAssessmentOutput = ProbabilityAssessmentService.Calculate(input, double.NaN);
+            var probabilityAssessmentOutput = ProbabilityAssessmentService.Calculate(norm, contribution, lengthEffectN, double.NaN);
 
             // Assert
             Assert.AreEqual(expectedResult, probabilityAssessmentOutput.RequiredProbability, probabilityAssessmentOutput.RequiredProbability.GetAccuracy());
@@ -77,16 +56,8 @@
         [TestCase(20000, 24, 1, 4.2240038)]
         public void RequiredReliability_DifferentInputs_ReturnsExpectedValue(int norm, double contribution, int lengthEffectN, double expectedResult)
         {
-            // Setup
-            var input = new ProbabilityAssessmentInput
-            {
-                Norm = norm,
-                Contribution = contribution,
-                N = lengthEffectN
-            };
-
             // Call
-            var probabilityAssessmentOutput = ProbabilityAssessmentService.Calculate(input, double.NaN);
+            var probabilityAssessmentOutput = ProbabilityAssessmentService.Calculate(norm, contribution, lengthEffectN, double.NaN);
 
             // Assert
             Assert.AreEqual(expectedResult, probabilityAssessmentOutput.RequiredReliability, probabilityAssessmentOutput.RequiredReliability.GetAccuracy());
@@ -97,11 +68,8 @@
         [TestCase(789.123, 789.123)]
         public void Reliability_DifferentInputs_ReturnsExpectedValue(double reliability, double expectedResult)
         {
-            // Setup
-            var input = new ProbabilityAssessmentInput();
-
             // Call
-            var probabilityAssessmentOutput = ProbabilityAssessmentService.Calculate(input, reliability);
+            var probabilityAssessmentOutput = ProbabilityAssessmentService.Calculate(double.NaN, double.NaN, double.NaN, reliability);
 
             // Assert
             Assert.AreEqual(expectedResult, probabilityAssessmentOutput.Reliability, probabilityAssessmentOutput.Reliability.GetAccuracy());
@@ -112,11 +80,8 @@
         [TestCase(5, 3488555.78723)]
         public void Probability_DifferentInputs_ReturnsExpectedValue(double reliability, double expectedResult)
         {
-            // Setup
-            var input = new ProbabilityAssessmentInput();
-
             // Call
-            var probabilityAssessmentOutput = ProbabilityAssessmentService.Calculate(input, reliability);
+            var probabilityAssessmentOutput = ProbabilityAssessmentService.Calculate(double.NaN, double.NaN, double.NaN, reliability);
 
             // Assert
             Assert.AreEqual(expectedResult, probabilityAssessmentOutput.Probability, probabilityAssessmentOutput.Probability.GetAccuracy());
@@ -133,16 +98,8 @@
         [TestCase(20000, 24, 2, 4.149409984, 0.947875892)]
         public void FactorOfSafety_DifferentInputs_ReturnsExpectedValue(int norm, double contribution, int lengthEffectN, double reliability, double expectedResult)
         {
-            // Setup
-            var input = new ProbabilityAssessmentInput
-            {
-                Norm = norm,
-                Contribution = contribution,
-                N = lengthEffectN
-            };
-
             // Call
-            var probabilityAssessmentOutput = ProbabilityAssessmentService.Calculate(input, reliability);
+            var probabilityAssessmentOutput = ProbabilityAssessmentService.Calculate(norm, contribution, lengthEffectN, reliability);
 
             // Assert
             Assert.AreEqual(expectedResult, probabilityAssessmentOutput.FactorOfSafety, probabilityAssessmentOutput.FactorOfSafety.GetAccuracy());
Index: Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Plugin/GrassCoverErosionInwardsGuiPlugin.cs
===================================================================
diff -u -r0e8590d1ba6edc87a2ac73240662bfcf45f20914 -r1957c54820f55f8de15e34add4577a78b2e96850
--- Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Plugin/GrassCoverErosionInwardsGuiPlugin.cs	(.../GrassCoverErosionInwardsGuiPlugin.cs)	(revision 0e8590d1ba6edc87a2ac73240662bfcf45f20914)
+++ Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Plugin/GrassCoverErosionInwardsGuiPlugin.cs	(.../GrassCoverErosionInwardsGuiPlugin.cs)	(revision 1957c54820f55f8de15e34add4577a78b2e96850)
@@ -211,7 +211,7 @@
         {
             if (output != null)
             {
-                calculation.Output = ProbabilityAssessmentService.Calculate(probabilityAssessmentInput, output.Beta);
+                calculation.Output = ProbabilityAssessmentService.Calculate(probabilityAssessmentInput.Norm, probabilityAssessmentInput.Contribution, probabilityAssessmentInput.N, output.Beta);
                 calculation.NotifyObservers();
             }
             else
Index: Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Plugin/HeightStructuresGuiPlugin.cs
===================================================================
diff -u -rea180de6e9f5ba1108b4ff3cf7bb7e57de72a37a -r1957c54820f55f8de15e34add4577a78b2e96850
--- Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Plugin/HeightStructuresGuiPlugin.cs	(.../HeightStructuresGuiPlugin.cs)	(revision ea180de6e9f5ba1108b4ff3cf7bb7e57de72a37a)
+++ Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Plugin/HeightStructuresGuiPlugin.cs	(.../HeightStructuresGuiPlugin.cs)	(revision 1957c54820f55f8de15e34add4577a78b2e96850)
@@ -206,7 +206,7 @@
         {
             if (output != null)
             {
-                calculation.Output = ProbabilityAssessmentService.Calculate(probabilityAssessmentInput, output.Beta);
+                calculation.Output = ProbabilityAssessmentService.Calculate(probabilityAssessmentInput.Norm, probabilityAssessmentInput.Contribution, probabilityAssessmentInput.N, output.Beta);
                 calculation.NotifyObservers();
             }
             else