eval_utils/evaluation.py

import pandas as pd

from causalml.metrics import *

class ModelEvaluator:
    def __init__(self, model, df_eval, X_names):
        self.model = model
        self.df_eval = df_eval
        self.X_names = X_names
    
    def predict_cate(self, discount):
        """
        Predicts the Conditional Average Treatment Effect (CATE) for a given discount level.
        """
        self.df_eval['cate'] = self.model.predict(
            X=self.df_eval[self.X_names].values, 
            treatment=self.df_eval['treatment_group_key'].values
        ).tolist()
        self.df_eval[['cate_discount_05', 'cate_discount_10', 'cate_discount_15']] = pd.DataFrame(
            self.df_eval.cate.tolist(), 
            index=self.df_eval.index
        )

    def eval_performance(self, discount):
        """
        Evaluates the model's performance for a specific discount, calculating Qini curves for conversion and benefit.
        """
        # Ensure CATE predictions are available
        if 'cate' not in self.df_eval.columns:
            self.predict_cate(discount)
        
        df_eval_disc = self.df_eval[self.df_eval['treatment_group_key'].isin(['control', discount])]
        df_eval_disc['treatment_num'] = df_eval_disc.apply(
            lambda x: 0 if x['treatment_group_key'] == 'control' else 1, 
            axis=1
        )

        cate_col = 'cate_{}'.format(discount)

        df_eval_qini_conversion = pd.DataFrame(
            [df_eval_disc[cate_col].ravel(), df_eval_disc.treatment_num.ravel(), df_eval_disc['conversion'].ravel()],
            index=['S', 'w', 'y']
        ).T

        df_eval_qini_benefit = pd.DataFrame(
            [df_eval_disc[cate_col].ravel(), df_eval_disc.treatment_num.ravel(), df_eval_disc['benefit'].ravel()],
            index=['S', 'w', 'y']
        ).T

        # Assuming get_qini function exists and calculates Qini coefficient
        cd_conversion = (get_qini(df_eval_qini_conversion) * 2).reset_index()
        cd_conversion = cd_conversion / cd_conversion.shape[0]

        cd_benefit = (get_qini(df_eval_qini_benefit) * 2).reset_index()
        cd_benefit = cd_benefit / cd_benefit.shape[0]

        return cd_conversion, cd_benefit