Difficulty of “learning” rare instances

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Is there any result showing that models (say SVM, Neural-Net, kNN, etc) will have difficulty in learning "rare" instances/tail phenomena?







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  • I think you accepted an answer too quickly -- it's a good answer, but there could be more possibilities out there as well.
    – usul
    Aug 8 at 8:35










  • @usul thanks for the comment. Do you have any further suggestion? Would be happy to hear additional thoughts.
    – Daniel
    Aug 8 at 14:13














up vote
8
down vote

favorite












Is there any result showing that models (say SVM, Neural-Net, kNN, etc) will have difficulty in learning "rare" instances/tail phenomena?







share|cite|improve this question




















  • I think you accepted an answer too quickly -- it's a good answer, but there could be more possibilities out there as well.
    – usul
    Aug 8 at 8:35










  • @usul thanks for the comment. Do you have any further suggestion? Would be happy to hear additional thoughts.
    – Daniel
    Aug 8 at 14:13












up vote
8
down vote

favorite









up vote
8
down vote

favorite











Is there any result showing that models (say SVM, Neural-Net, kNN, etc) will have difficulty in learning "rare" instances/tail phenomena?







share|cite|improve this question












Is there any result showing that models (say SVM, Neural-Net, kNN, etc) will have difficulty in learning "rare" instances/tail phenomena?









share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Aug 7 at 15:53









Daniel

484312




484312











  • I think you accepted an answer too quickly -- it's a good answer, but there could be more possibilities out there as well.
    – usul
    Aug 8 at 8:35










  • @usul thanks for the comment. Do you have any further suggestion? Would be happy to hear additional thoughts.
    – Daniel
    Aug 8 at 14:13
















  • I think you accepted an answer too quickly -- it's a good answer, but there could be more possibilities out there as well.
    – usul
    Aug 8 at 8:35










  • @usul thanks for the comment. Do you have any further suggestion? Would be happy to hear additional thoughts.
    – Daniel
    Aug 8 at 14:13















I think you accepted an answer too quickly -- it's a good answer, but there could be more possibilities out there as well.
– usul
Aug 8 at 8:35




I think you accepted an answer too quickly -- it's a good answer, but there could be more possibilities out there as well.
– usul
Aug 8 at 8:35












@usul thanks for the comment. Do you have any further suggestion? Would be happy to hear additional thoughts.
– Daniel
Aug 8 at 14:13




@usul thanks for the comment. Do you have any further suggestion? Would be happy to hear additional thoughts.
– Daniel
Aug 8 at 14:13










1 Answer
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In the classic PAC learning (i.e., classification) model, rare instances are not a problem. This is because the learner's test points are assumed to come from the same distribution as the training data. Thus, if a region of space is so sparse as to be poorly represented in the training sample, its probability of appearing during the test phase is low.



You'll need a different learning model, which explicitly looks at type-I and type-II errors, or perhaps some combined precision-recall score. Here again, I don't think there are any results indicating that a specific class of algorithms is particularly poorly suited for this task, but I could be wrong.



The closest I can think of is sensitivity to outliers --- AdaBoost is known to have this property, for example.






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    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes








    up vote
    10
    down vote



    accepted










    In the classic PAC learning (i.e., classification) model, rare instances are not a problem. This is because the learner's test points are assumed to come from the same distribution as the training data. Thus, if a region of space is so sparse as to be poorly represented in the training sample, its probability of appearing during the test phase is low.



    You'll need a different learning model, which explicitly looks at type-I and type-II errors, or perhaps some combined precision-recall score. Here again, I don't think there are any results indicating that a specific class of algorithms is particularly poorly suited for this task, but I could be wrong.



    The closest I can think of is sensitivity to outliers --- AdaBoost is known to have this property, for example.






    share|cite|improve this answer
























      up vote
      10
      down vote



      accepted










      In the classic PAC learning (i.e., classification) model, rare instances are not a problem. This is because the learner's test points are assumed to come from the same distribution as the training data. Thus, if a region of space is so sparse as to be poorly represented in the training sample, its probability of appearing during the test phase is low.



      You'll need a different learning model, which explicitly looks at type-I and type-II errors, or perhaps some combined precision-recall score. Here again, I don't think there are any results indicating that a specific class of algorithms is particularly poorly suited for this task, but I could be wrong.



      The closest I can think of is sensitivity to outliers --- AdaBoost is known to have this property, for example.






      share|cite|improve this answer






















        up vote
        10
        down vote



        accepted







        up vote
        10
        down vote



        accepted






        In the classic PAC learning (i.e., classification) model, rare instances are not a problem. This is because the learner's test points are assumed to come from the same distribution as the training data. Thus, if a region of space is so sparse as to be poorly represented in the training sample, its probability of appearing during the test phase is low.



        You'll need a different learning model, which explicitly looks at type-I and type-II errors, or perhaps some combined precision-recall score. Here again, I don't think there are any results indicating that a specific class of algorithms is particularly poorly suited for this task, but I could be wrong.



        The closest I can think of is sensitivity to outliers --- AdaBoost is known to have this property, for example.






        share|cite|improve this answer












        In the classic PAC learning (i.e., classification) model, rare instances are not a problem. This is because the learner's test points are assumed to come from the same distribution as the training data. Thus, if a region of space is so sparse as to be poorly represented in the training sample, its probability of appearing during the test phase is low.



        You'll need a different learning model, which explicitly looks at type-I and type-II errors, or perhaps some combined precision-recall score. Here again, I don't think there are any results indicating that a specific class of algorithms is particularly poorly suited for this task, but I could be wrong.



        The closest I can think of is sensitivity to outliers --- AdaBoost is known to have this property, for example.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Aug 7 at 17:59









        Aryeh

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