emphasise some observation weights more than the others












0












$begingroup$


I want to emphasise (increase the weight) of only a subset of data. Lets say I have old and fresh data, I would like to say that old data has to have more weight and therefore has more influence in the decision than the new data.



In scikit-learn I found only class-weight parameter, but it does not change the weight of the samples, only of all samples within the class.



Is there a way to incorporate this emphasis into the gradient boosted trees in spark or xgboost in python?










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bumped to the homepage by Community 19 hours ago


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  • 2




    $begingroup$
    Are you sure it does that? The documentation suggests otherwise; see sample_weight_last_ten.
    $endgroup$
    – Emre
    Apr 16 '18 at 20:34


















0












$begingroup$


I want to emphasise (increase the weight) of only a subset of data. Lets say I have old and fresh data, I would like to say that old data has to have more weight and therefore has more influence in the decision than the new data.



In scikit-learn I found only class-weight parameter, but it does not change the weight of the samples, only of all samples within the class.



Is there a way to incorporate this emphasis into the gradient boosted trees in spark or xgboost in python?










share|improve this question









$endgroup$




bumped to the homepage by Community 19 hours ago


This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.











  • 2




    $begingroup$
    Are you sure it does that? The documentation suggests otherwise; see sample_weight_last_ten.
    $endgroup$
    – Emre
    Apr 16 '18 at 20:34
















0












0








0





$begingroup$


I want to emphasise (increase the weight) of only a subset of data. Lets say I have old and fresh data, I would like to say that old data has to have more weight and therefore has more influence in the decision than the new data.



In scikit-learn I found only class-weight parameter, but it does not change the weight of the samples, only of all samples within the class.



Is there a way to incorporate this emphasis into the gradient boosted trees in spark or xgboost in python?










share|improve this question









$endgroup$




I want to emphasise (increase the weight) of only a subset of data. Lets say I have old and fresh data, I would like to say that old data has to have more weight and therefore has more influence in the decision than the new data.



In scikit-learn I found only class-weight parameter, but it does not change the weight of the samples, only of all samples within the class.



Is there a way to incorporate this emphasis into the gradient boosted trees in spark or xgboost in python?







weighted-data






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Apr 16 '18 at 11:45









TonjaTonja

1033




1033





bumped to the homepage by Community 19 hours ago


This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.







bumped to the homepage by Community 19 hours ago


This question has answers that may be good or bad; the system has marked it active so that they can be reviewed.










  • 2




    $begingroup$
    Are you sure it does that? The documentation suggests otherwise; see sample_weight_last_ten.
    $endgroup$
    – Emre
    Apr 16 '18 at 20:34
















  • 2




    $begingroup$
    Are you sure it does that? The documentation suggests otherwise; see sample_weight_last_ten.
    $endgroup$
    – Emre
    Apr 16 '18 at 20:34










2




2




$begingroup$
Are you sure it does that? The documentation suggests otherwise; see sample_weight_last_ten.
$endgroup$
– Emre
Apr 16 '18 at 20:34






$begingroup$
Are you sure it does that? The documentation suggests otherwise; see sample_weight_last_ten.
$endgroup$
– Emre
Apr 16 '18 at 20:34












2 Answers
2






active

oldest

votes


















1












$begingroup$

If you have a date variable (or something similar), you can create a weight using this.



If you're using XGBoost, there is an option to specify a weight for each instance when creating the DMatrix - feed your observation weighting in here.






share|improve this answer









$endgroup$





















    0












    $begingroup$

    There might be a fancier way to create dynamic weights but I would probably start with oversampling the subset and see how that goes. So if you've got classes A, B, and C and want to emphasize C, make a duplicate copy of C and insert that into your training data. In other words, assume you have six records to train on:




    1. A1

    2. A2

    3. B1

    4. B2

    5. C1

    6. C2


    add:




    1. C1

    2. C2






    share|improve this answer









    $endgroup$









    • 1




      $begingroup$
      You should be very wary of this method as it may introduce biases and skewness into your data - e.g. the distribution of certain variables may change.
      $endgroup$
      – bradS
      May 17 '18 at 8:00












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    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    1












    $begingroup$

    If you have a date variable (or something similar), you can create a weight using this.



    If you're using XGBoost, there is an option to specify a weight for each instance when creating the DMatrix - feed your observation weighting in here.






    share|improve this answer









    $endgroup$


















      1












      $begingroup$

      If you have a date variable (or something similar), you can create a weight using this.



      If you're using XGBoost, there is an option to specify a weight for each instance when creating the DMatrix - feed your observation weighting in here.






      share|improve this answer









      $endgroup$
















        1












        1








        1





        $begingroup$

        If you have a date variable (or something similar), you can create a weight using this.



        If you're using XGBoost, there is an option to specify a weight for each instance when creating the DMatrix - feed your observation weighting in here.






        share|improve this answer









        $endgroup$



        If you have a date variable (or something similar), you can create a weight using this.



        If you're using XGBoost, there is an option to specify a weight for each instance when creating the DMatrix - feed your observation weighting in here.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered May 17 '18 at 8:02









        bradSbradS

        667213




        667213























            0












            $begingroup$

            There might be a fancier way to create dynamic weights but I would probably start with oversampling the subset and see how that goes. So if you've got classes A, B, and C and want to emphasize C, make a duplicate copy of C and insert that into your training data. In other words, assume you have six records to train on:




            1. A1

            2. A2

            3. B1

            4. B2

            5. C1

            6. C2


            add:




            1. C1

            2. C2






            share|improve this answer









            $endgroup$









            • 1




              $begingroup$
              You should be very wary of this method as it may introduce biases and skewness into your data - e.g. the distribution of certain variables may change.
              $endgroup$
              – bradS
              May 17 '18 at 8:00
















            0












            $begingroup$

            There might be a fancier way to create dynamic weights but I would probably start with oversampling the subset and see how that goes. So if you've got classes A, B, and C and want to emphasize C, make a duplicate copy of C and insert that into your training data. In other words, assume you have six records to train on:




            1. A1

            2. A2

            3. B1

            4. B2

            5. C1

            6. C2


            add:




            1. C1

            2. C2






            share|improve this answer









            $endgroup$









            • 1




              $begingroup$
              You should be very wary of this method as it may introduce biases and skewness into your data - e.g. the distribution of certain variables may change.
              $endgroup$
              – bradS
              May 17 '18 at 8:00














            0












            0








            0





            $begingroup$

            There might be a fancier way to create dynamic weights but I would probably start with oversampling the subset and see how that goes. So if you've got classes A, B, and C and want to emphasize C, make a duplicate copy of C and insert that into your training data. In other words, assume you have six records to train on:




            1. A1

            2. A2

            3. B1

            4. B2

            5. C1

            6. C2


            add:




            1. C1

            2. C2






            share|improve this answer









            $endgroup$



            There might be a fancier way to create dynamic weights but I would probably start with oversampling the subset and see how that goes. So if you've got classes A, B, and C and want to emphasize C, make a duplicate copy of C and insert that into your training data. In other words, assume you have six records to train on:




            1. A1

            2. A2

            3. B1

            4. B2

            5. C1

            6. C2


            add:




            1. C1

            2. C2







            share|improve this answer












            share|improve this answer



            share|improve this answer










            answered Apr 16 '18 at 18:51









            CalZCalZ

            1,438213




            1,438213








            • 1




              $begingroup$
              You should be very wary of this method as it may introduce biases and skewness into your data - e.g. the distribution of certain variables may change.
              $endgroup$
              – bradS
              May 17 '18 at 8:00














            • 1




              $begingroup$
              You should be very wary of this method as it may introduce biases and skewness into your data - e.g. the distribution of certain variables may change.
              $endgroup$
              – bradS
              May 17 '18 at 8:00








            1




            1




            $begingroup$
            You should be very wary of this method as it may introduce biases and skewness into your data - e.g. the distribution of certain variables may change.
            $endgroup$
            – bradS
            May 17 '18 at 8:00




            $begingroup$
            You should be very wary of this method as it may introduce biases and skewness into your data - e.g. the distribution of certain variables may change.
            $endgroup$
            – bradS
            May 17 '18 at 8:00


















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