RM 9.4 feedback (official release) : Costs/Benefits calculation

lionelderkrikorlionelderkrikor Moderator, RapidMiner Certified Analyst, Member Posts: 1,195 Unicorn
Dear all,

First thanks you for implementing the costs/benefits calculus in this new release - I think lot of users (including me) waited for this new feature.

2 months ago I had several questions in this thread about the Costs/Benefits calcultation and thanks to @IngoRM to answer me, that's was clear : 


But in this official release , I'm seeing that "Total Cost/Benefit (expected) and the associated average were abandoned. My first question is why ?

 The "Total Cost/Benefit (expected)" and the associated average are replaced by : 
 - "Total for best option"
 - "Gain"

My second question is  : can you explain how this 2 numbers are calculated (despite my efforts i was not able to retrieve them) and why these 2 new numbers are more relevant than the "Total Cost/Benefit (expected)" ?

Here my attempt to retrieve these 2 numbers with the Titanic Dataset with all options by default in AutoModel with NB model : 

Third question : in the new column called "cost" why the cost is not counted as negative when the prediction is wrong (I suppose the following cost matrix as the following) :


Thanks you for your listening,



Best Answers


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    lionelderkrikorlionelderkrikor Moderator, RapidMiner Certified Analyst, Member Posts: 1,195 Unicorn
    Hi Ingo,

    Yes, your long and detailed explanation helps me a lot to understand these new concepts of Benefits/Costs. #noblackboxes  :)
    Thank you for spending your time answering my questions.

    Now you'll think I'm picky about the details, but I will quote the deutsch philosopher Friedrich Nietzsche : "The Devil is in the details"  >:)
    I begin  : 
    The 3 money indicators (Total Cost/Benefits, Total for Best Option, Gain) are calculated on the whole validation set (ie for the Titanic dataset on 524 examples [1309 examples x 40%]) : 

    But the displayed confusion matrix is NOT builded on the whole validation test : 

    Here we can see that the number of examples used to build this confusion matrix (always for the Titanic) is 
    219 + 135 + 7 + 14 = 375 examples A priori due to the factor 5 /7 introduced by the Performance Average (Robust) operator.

    My question is for a question of homogeneity of the results, should the 3 moneys indicators not be calculated with this displayed confusion matrix ? In other words, actually, the displayed money indicators don't correspond directly to the displayed confusion matrix ...

    Thanks you for your patience and your listening...



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    lionelderkrikorlionelderkrikor Moderator, RapidMiner Certified Analyst, Member Posts: 1,195 Unicorn
    You got me there
    So Friedrich Nietzsche was right ..... >:)

    More seriouly, I agree with your point of view, Ingo,  and once again, thanks for taking the time to answer me.


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    Telcontar120Telcontar120 Moderator, RapidMiner Certified Analyst, RapidMiner Certified Expert, Member Posts: 1,635 Unicorn
    This is a very interesting discussion.  I haven't had a chance to dive into this new operator yet, but I had a couple of questions.
    @IngoRM how is the new operator different from the existing Performance(Costs) operator?  Or is it?
    It appears that they require the same inputs (a class order and then a misclassification cost matrix). In this framework, are you still allowed to enter benefits as negative costs?

    Brian T.
    Lindon Ventures 
    Data Science Consulting from Certified RapidMiner Experts
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