Computer system and data analysis method

Abstract

A computer system is provided, which is capable of evaluating the degree of influence of training data on prediction accuracy of a decision tree type machine learning model, while suppressing increase in processing time thereof. A similarity score calculating unit uses a tree structure of a trained model of a target predictor to calculate, for each of training data used for learning this trained model, a similarity score in which is evaluated similarity between the training data in the trained model and other training data. An evaluating unit selects target data that is training data that is a target of evaluation from the training dataset on the basis of the similarity score, and calculates an influence score in which the degree of influence of the target data on accuracy of the trained model is evaluated.