DecisiontreeClassifier, why is the sum of values wrong?

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I visualized my decisiontreeclassifier and I noticed, that the sum of samples are wrong or formulated differently the 'value' value does not fit with the value of the samples(Screenshot)? Do I misinterpret my Decisiontree? I thought if got 100 samples in my node and 40 are True and 60 are False, I got in my next node 40 (or 60) samples which are divided again...

import matplotlib.pyplot as plt
from sklearn import tree
tree1=DecisionTreeClassifier(criterion="entropy",max_features=13,max_leaf_nodes=75,min_impurity_decrease=0.001,min_samples_leaf=12,min_samples_split=20,splitter="best",max_depth=9)

tree1.fit(X_train,y_train)
feature_names=Daten.drop("Abwanderung_LabelEncode",axis=1).columns
class_names=["Keine Abwanderung","Abwanderung"]
fig = plt.figure(figsize=(25,20))
_ = tree.plot_tree(tree1, 
               feature_names=feature_names,
               class_names=class_names,
               rounded=True,
               filled=True)

Screenshot of a part of my decisiontree

scikit-learn decision-tree matplotlib python
2 Answers

The plot is correct.

The two values in value are not the number of samples to go to the children nodes; instead, they are the negative and positive class counts in the node. For example, 748=101+647; there are 748 samples in that node, 647 of which are positive class. The child nodes have 685 and 63 samples, and 685+63=647. The left child has 47 of the negative samples, and the right node 54, and 47+54=101, the total number of negative samples.

user_104958930

The value field does not represent the size of the split but rather how many data points are present for each class. For example, the split at the top node voicemail_tarif_labelencode <= 0.5 has 748 samples and 101 belong to class at index 0 and 647 belong to class at index 1. It does not show the number of data points <= 0.5 and those > 0.5. If you now look at the next two nodes the sum of those sample sizes (685 + 63) = 748 which is the number of samples in the parent node.

user_4903320
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