title: Machine learning - Score column is missing
body: <p>I'm trying out the ML.net framework with some random test data. My data exists of a DepartmentId (1-25) and a Body (string). I want my machine to predict the department that the body should be allocated (for example in a ticket system like Zendesk).</p>
  
  <p>Using the following code, I'm receving an error:</p>
  
  <blockquote>
    <p>ArgumentOutOfRangeException: Score column is missing</p>
  </blockquote>
  
  <p>I'm not sure why it says that the <code>Score</code> column is missing, as it's present in my prediction class.</p>
  
  <p>Here's my setup for training the model, as well as my classes.</p>
  
  <p><strong>Main</strong></p>
  
  <pre><code>var pipeline = new LearningPipeline();
  pipeline.Add(new TextLoader(_dataPath).CreateFrom&lt;DepartmentData&gt;(userHeader: true, seperator: ','));
  pipeline.Add(new TextFeaturizer("Features", "Body"));
  pipeline.Add(new Dictionarizer("Label"));
  pipeline.Add(new StochasticDualCoordinateAscentClassifier());
  pipeline.Add(new PredictedLabelColumnOriginalValueConverter() { PredictedLabelColumn = "PredictedLabel" });
  
  var model = pipeline.Train&lt;DepartmentData, DepartmentPrediction&gt;();
  </code></pre>
  
  <p><strong>DepartmentData and DepartmentPrediction</strong></p>
  
  <pre><code>public class DepartmentData
  {
      [Column(ordinal: "0", name: "Label")]
      public float Department;
      [Column(ordinal: "1")]
      public string Body;
  }
  
  public class DepartmentPrediction
  {
      [ColumnName("PredictedLabel")]
      public float Department;
  
      [ColumnName("Score")]
      public float[] Score;
  }
  </code></pre>
  
  <p><strong>Example data</strong></p>
  
  <pre><code>Department, Body
  1, Hello. 4 weeks ago I requested a replacement keycap for my keyboard. I still ahvent received the keycap. Perhaps you can confirm that it has been shipped?
  13, I seem to have some problems when paying for you new mouse XZ-250 I'm being told that my card is not valid?
  1, I just received the package I bought from you but I'm most definetly not satisfied with the shipment. The box was bended and broken when it received as well as the GPU inside. I demand that you ship a new one to me without charge. I've attached a few images of the box and the GPU here.
  /* etc... */
  </code></pre>
  
  <p><strong>Evaluation</strong></p>
  
  <pre><code>var testData = new TextLoader(_testDataPath).CreateFrom&lt;DepartmentData&gt;(useHeader: true, seperator: ',');
  var evaluator = new ClassificationEvaluator();
  var metrics = evaluator.Evaluate(model, testData);
  </code></pre>