Should I oversample my validation data to get better F1 score and PRC?












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I am currently working with a dataset that is imbalanced, about 30k rows * 14 features (just for you know), and 99.5% of the data is labeled 0. Since the model is strongly imbalanced I decided to use precision/recall/f1 score to decide the performance of model.



I used SMOTE to oversample my training data (after splitting the validation set out). Now my model is trained with oversampled training data, and I am going to test it with validation set. If I just validate it on original validation data, I get a F1 score around 0.05, and the classification report is followed:



          precision    recall  f1-score   support

Class 0 1.00 0.86 0.93 7606
Class 1 0.03 0.75 0.05 36


If I oversample my validation data, I get a F1 score around 0.85:



          precision    recall  f1-score   support

Class 0 0.84 0.86 0.85 7606
Class 1 0.86 0.83 0.85 7606


My question is:




  1. Should I use an oversampled validation set? (because the result is much prettier but I think the model is the same anyway)


  2. Why do I have such bad metrics on the original validation data? Is it because the data size is not big enough?



(This is my first time posting so please be gentle if I did or said anything wrong!)










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    $begingroup$


    I am currently working with a dataset that is imbalanced, about 30k rows * 14 features (just for you know), and 99.5% of the data is labeled 0. Since the model is strongly imbalanced I decided to use precision/recall/f1 score to decide the performance of model.



    I used SMOTE to oversample my training data (after splitting the validation set out). Now my model is trained with oversampled training data, and I am going to test it with validation set. If I just validate it on original validation data, I get a F1 score around 0.05, and the classification report is followed:



              precision    recall  f1-score   support

    Class 0 1.00 0.86 0.93 7606
    Class 1 0.03 0.75 0.05 36


    If I oversample my validation data, I get a F1 score around 0.85:



              precision    recall  f1-score   support

    Class 0 0.84 0.86 0.85 7606
    Class 1 0.86 0.83 0.85 7606


    My question is:




    1. Should I use an oversampled validation set? (because the result is much prettier but I think the model is the same anyway)


    2. Why do I have such bad metrics on the original validation data? Is it because the data size is not big enough?



    (This is my first time posting so please be gentle if I did or said anything wrong!)










    share|improve this question







    New contributor




    Frank Xu is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
    Check out our Code of Conduct.







    $endgroup$















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      0





      $begingroup$


      I am currently working with a dataset that is imbalanced, about 30k rows * 14 features (just for you know), and 99.5% of the data is labeled 0. Since the model is strongly imbalanced I decided to use precision/recall/f1 score to decide the performance of model.



      I used SMOTE to oversample my training data (after splitting the validation set out). Now my model is trained with oversampled training data, and I am going to test it with validation set. If I just validate it on original validation data, I get a F1 score around 0.05, and the classification report is followed:



                precision    recall  f1-score   support

      Class 0 1.00 0.86 0.93 7606
      Class 1 0.03 0.75 0.05 36


      If I oversample my validation data, I get a F1 score around 0.85:



                precision    recall  f1-score   support

      Class 0 0.84 0.86 0.85 7606
      Class 1 0.86 0.83 0.85 7606


      My question is:




      1. Should I use an oversampled validation set? (because the result is much prettier but I think the model is the same anyway)


      2. Why do I have such bad metrics on the original validation data? Is it because the data size is not big enough?



      (This is my first time posting so please be gentle if I did or said anything wrong!)










      share|improve this question







      New contributor




      Frank Xu is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.







      $endgroup$




      I am currently working with a dataset that is imbalanced, about 30k rows * 14 features (just for you know), and 99.5% of the data is labeled 0. Since the model is strongly imbalanced I decided to use precision/recall/f1 score to decide the performance of model.



      I used SMOTE to oversample my training data (after splitting the validation set out). Now my model is trained with oversampled training data, and I am going to test it with validation set. If I just validate it on original validation data, I get a F1 score around 0.05, and the classification report is followed:



                precision    recall  f1-score   support

      Class 0 1.00 0.86 0.93 7606
      Class 1 0.03 0.75 0.05 36


      If I oversample my validation data, I get a F1 score around 0.85:



                precision    recall  f1-score   support

      Class 0 0.84 0.86 0.85 7606
      Class 1 0.86 0.83 0.85 7606


      My question is:




      1. Should I use an oversampled validation set? (because the result is much prettier but I think the model is the same anyway)


      2. Why do I have such bad metrics on the original validation data? Is it because the data size is not big enough?



      (This is my first time posting so please be gentle if I did or said anything wrong!)







      machine-learning classification cross-validation confusion-matrix smote






      share|improve this question







      New contributor




      Frank Xu is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.











      share|improve this question







      New contributor




      Frank Xu is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.









      share|improve this question




      share|improve this question






      New contributor




      Frank Xu is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.









      asked 14 mins ago









      Frank XuFrank Xu

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      New contributor





      Frank Xu is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
      Check out our Code of Conduct.






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      Check out our Code of Conduct.






















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