A method for detecting whether an input variable for a machine learning system is suitable as an additional training datum or test datum for the machine learning system for retraining and testing. The method includes: processing a detected input variable by way of the machine learning system, intermediate results which are ascertained during the processing of the input variable by the machine learning system being stored; processing the stored intermediate results by way of an anomaly detector, the anomaly detector outputting an output variable which characterizes whether the detected input variable associated with the intermediate results yields an anomalous behavior of the machine learning system; based on the output variable of the network, the input variable of the network and the additional input variables defined as relevant are stored/selected. A computer system, computer program, and a machine-readable memory element on which the computer program is stored are also described.