Abstract: A non-transitory computer-readable storage medium for storing a determination processing program which causes a processor to perform processing that includes: obtaining an importance degree vector for a plurality of feature amounts by training a first machine learning model based on machine-learning data, the machine-learning data including pieces of training data, each of the pieces of training data including the plurality of feature amounts and being associated with a corresponding determination result; training a second machine learning model of a k-nearest neighbors algorithm in accordance with the machine-learning data and the importance degree vector; and determining, from among the pieces of training data, a piece of data that is similar to data to be predicted, by using the trained second machine learning model and the data to be predicted.