Neural Net Accuracy: Test Set vs Real World Data Announcing the arrival of Valued Associate #679: Cesar Manara Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern) 2019 Moderator Election Q&A - Questionnaire 2019 Community Moderator Election ResultsNeural Networks: How to prepare real world data to detect low probability events?Preparing custom dataset for object detection using MLHow to maximize recall?Any difference between adding epochs and duplicating data for neural nets?Why would 2 sets of similar training samples take significantly longer to train?Keras intuition/guidelines for setting epochs and batch sizeExpected behaviour of loss and accuracy when using data augmentationOwn Implementation of Neural Networks heavily under fitting the dataNeural Network Data Normalization SetupWhy real-world output of my classifier has similar label ratio to training data?

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Neural Net Accuracy: Test Set vs Real World Data



Announcing the arrival of Valued Associate #679: Cesar Manara
Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern)
2019 Moderator Election Q&A - Questionnaire
2019 Community Moderator Election ResultsNeural Networks: How to prepare real world data to detect low probability events?Preparing custom dataset for object detection using MLHow to maximize recall?Any difference between adding epochs and duplicating data for neural nets?Why would 2 sets of similar training samples take significantly longer to train?Keras intuition/guidelines for setting epochs and batch sizeExpected behaviour of loss and accuracy when using data augmentationOwn Implementation of Neural Networks heavily under fitting the dataNeural Network Data Normalization SetupWhy real-world output of my classifier has similar label ratio to training data?










0












$begingroup$


Neural Net accuracy is high on test set but low on new real world image examples.



Looking for advice regarding what generally causes this scenario and how to fix it.



Sampling basis? Training/test set is not representative of real world data? Obtain more training/test data?










share|improve this question









New contributor




joshvarial is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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$endgroup$







  • 1




    $begingroup$
    Probably your train and test set are not representative, but it is impossible to tell with no information. Can you tell the difference between train/test and real world data yourself? Can you show samples? How much data do you have? More relevant information will be helpful in getting you good answers.
    $endgroup$
    – Simon Larsson
    Apr 12 at 7:08










  • $begingroup$
    Train/test/real world data are of the same format/quality. ~10,000 positive training examples and ~10,000 negative training examples for binary classification.
    $endgroup$
    – joshvarial
    Apr 13 at 2:00















0












$begingroup$


Neural Net accuracy is high on test set but low on new real world image examples.



Looking for advice regarding what generally causes this scenario and how to fix it.



Sampling basis? Training/test set is not representative of real world data? Obtain more training/test data?










share|improve this question









New contributor




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







$endgroup$







  • 1




    $begingroup$
    Probably your train and test set are not representative, but it is impossible to tell with no information. Can you tell the difference between train/test and real world data yourself? Can you show samples? How much data do you have? More relevant information will be helpful in getting you good answers.
    $endgroup$
    – Simon Larsson
    Apr 12 at 7:08










  • $begingroup$
    Train/test/real world data are of the same format/quality. ~10,000 positive training examples and ~10,000 negative training examples for binary classification.
    $endgroup$
    – joshvarial
    Apr 13 at 2:00













0












0








0





$begingroup$


Neural Net accuracy is high on test set but low on new real world image examples.



Looking for advice regarding what generally causes this scenario and how to fix it.



Sampling basis? Training/test set is not representative of real world data? Obtain more training/test data?










share|improve this question









New contributor




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







$endgroup$




Neural Net accuracy is high on test set but low on new real world image examples.



Looking for advice regarding what generally causes this scenario and how to fix it.



Sampling basis? Training/test set is not representative of real world data? Obtain more training/test data?







neural-network deep-learning keras tensorflow image-classification






share|improve this question









New contributor




joshvarial 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




joshvarial 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








edited 9 mins ago







joshvarial













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asked Apr 12 at 6:57









joshvarialjoshvarial

262




262




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New contributor





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






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







  • 1




    $begingroup$
    Probably your train and test set are not representative, but it is impossible to tell with no information. Can you tell the difference between train/test and real world data yourself? Can you show samples? How much data do you have? More relevant information will be helpful in getting you good answers.
    $endgroup$
    – Simon Larsson
    Apr 12 at 7:08










  • $begingroup$
    Train/test/real world data are of the same format/quality. ~10,000 positive training examples and ~10,000 negative training examples for binary classification.
    $endgroup$
    – joshvarial
    Apr 13 at 2:00












  • 1




    $begingroup$
    Probably your train and test set are not representative, but it is impossible to tell with no information. Can you tell the difference between train/test and real world data yourself? Can you show samples? How much data do you have? More relevant information will be helpful in getting you good answers.
    $endgroup$
    – Simon Larsson
    Apr 12 at 7:08










  • $begingroup$
    Train/test/real world data are of the same format/quality. ~10,000 positive training examples and ~10,000 negative training examples for binary classification.
    $endgroup$
    – joshvarial
    Apr 13 at 2:00







1




1




$begingroup$
Probably your train and test set are not representative, but it is impossible to tell with no information. Can you tell the difference between train/test and real world data yourself? Can you show samples? How much data do you have? More relevant information will be helpful in getting you good answers.
$endgroup$
– Simon Larsson
Apr 12 at 7:08




$begingroup$
Probably your train and test set are not representative, but it is impossible to tell with no information. Can you tell the difference between train/test and real world data yourself? Can you show samples? How much data do you have? More relevant information will be helpful in getting you good answers.
$endgroup$
– Simon Larsson
Apr 12 at 7:08












$begingroup$
Train/test/real world data are of the same format/quality. ~10,000 positive training examples and ~10,000 negative training examples for binary classification.
$endgroup$
– joshvarial
Apr 13 at 2:00




$begingroup$
Train/test/real world data are of the same format/quality. ~10,000 positive training examples and ~10,000 negative training examples for binary classification.
$endgroup$
– joshvarial
Apr 13 at 2:00










1 Answer
1






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oldest

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1












$begingroup$

Many resources teach the process of splitting data into training, validation and test sets. This is what you want to do for "closed" datasets where it's not possible to get additional data.



This assumption of a closed dataset is often not true in the real world, where it may be feasible to collect more data. Statistically speaking, it is a lot more desirable to define a test set as a new data sample that was collected separately from your training data. This might be more representative of how the model will behave in production, but sometimes even this is not enough:



A few weeks back I built an image classifier for cars. I trained it using a mix of existing datasets and the results of a web scrape. Ultimately, it was deployed through an iOS app where it was supposed to do make predictions in real time. In this case, it was not enough to just create a test split or collect a new sample from the web. We needed to shoot our own images that were representative for the use case in order to make realistic assumptions about the app's performance.






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    1












    $begingroup$

    Many resources teach the process of splitting data into training, validation and test sets. This is what you want to do for "closed" datasets where it's not possible to get additional data.



    This assumption of a closed dataset is often not true in the real world, where it may be feasible to collect more data. Statistically speaking, it is a lot more desirable to define a test set as a new data sample that was collected separately from your training data. This might be more representative of how the model will behave in production, but sometimes even this is not enough:



    A few weeks back I built an image classifier for cars. I trained it using a mix of existing datasets and the results of a web scrape. Ultimately, it was deployed through an iOS app where it was supposed to do make predictions in real time. In this case, it was not enough to just create a test split or collect a new sample from the web. We needed to shoot our own images that were representative for the use case in order to make realistic assumptions about the app's performance.






    share|improve this answer








    New contributor




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






    $endgroup$

















      1












      $begingroup$

      Many resources teach the process of splitting data into training, validation and test sets. This is what you want to do for "closed" datasets where it's not possible to get additional data.



      This assumption of a closed dataset is often not true in the real world, where it may be feasible to collect more data. Statistically speaking, it is a lot more desirable to define a test set as a new data sample that was collected separately from your training data. This might be more representative of how the model will behave in production, but sometimes even this is not enough:



      A few weeks back I built an image classifier for cars. I trained it using a mix of existing datasets and the results of a web scrape. Ultimately, it was deployed through an iOS app where it was supposed to do make predictions in real time. In this case, it was not enough to just create a test split or collect a new sample from the web. We needed to shoot our own images that were representative for the use case in order to make realistic assumptions about the app's performance.






      share|improve this answer








      New contributor




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






      $endgroup$















        1












        1








        1





        $begingroup$

        Many resources teach the process of splitting data into training, validation and test sets. This is what you want to do for "closed" datasets where it's not possible to get additional data.



        This assumption of a closed dataset is often not true in the real world, where it may be feasible to collect more data. Statistically speaking, it is a lot more desirable to define a test set as a new data sample that was collected separately from your training data. This might be more representative of how the model will behave in production, but sometimes even this is not enough:



        A few weeks back I built an image classifier for cars. I trained it using a mix of existing datasets and the results of a web scrape. Ultimately, it was deployed through an iOS app where it was supposed to do make predictions in real time. In this case, it was not enough to just create a test split or collect a new sample from the web. We needed to shoot our own images that were representative for the use case in order to make realistic assumptions about the app's performance.






        share|improve this answer








        New contributor




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






        $endgroup$



        Many resources teach the process of splitting data into training, validation and test sets. This is what you want to do for "closed" datasets where it's not possible to get additional data.



        This assumption of a closed dataset is often not true in the real world, where it may be feasible to collect more data. Statistically speaking, it is a lot more desirable to define a test set as a new data sample that was collected separately from your training data. This might be more representative of how the model will behave in production, but sometimes even this is not enough:



        A few weeks back I built an image classifier for cars. I trained it using a mix of existing datasets and the results of a web scrape. Ultimately, it was deployed through an iOS app where it was supposed to do make predictions in real time. In this case, it was not enough to just create a test split or collect a new sample from the web. We needed to shoot our own images that were representative for the use case in order to make realistic assumptions about the app's performance.







        share|improve this answer








        New contributor




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        share|improve this answer






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        answered Apr 12 at 10:22









        pietzpietz

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