Handling imbalanced data with XGboost:: Class_weight parameter

The Data Beast
2 min readApr 12, 2023

In XGBoost, the class_weight the parameter is used to adjust the weights of different classes in the training data to handle imbalanced class distribution. The class_weight parameter can be set to either "balanced" or a dictionary of weights for each class.

When class_weight is set to "balanced", XGBoost automatically adjusts the weights based on the number of samples in each class. For example, if one class has fewer samples than the others, its weight will be increased to make it more important during training.

If you want to manually set the weights for each class, you can provide a dictionary where the keys are the class labels and the values are the corresponding weights. For example, if you have two classes with labels 0 and 1, and you want to give class 1 a weight of 2 and class 0 a weight of 1, you can set class_weight={0:1, 1:2}.

Here is an example of setting the class_weight the parameter in XGBoost:

import xgboost as xgb

# create XGBoost classifier with class_weight parameter
clf = xgb.XGBClassifier(class_weight={0:1, 1:2})

In the above example, class 1 will be weighted twice as much as class 0 during training.

The choice of class weights for XGBoost depends on the specific problem and data being…

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