1. A computer-implemented method for predicting the condition of a component or system, in particular for an aircraft or spacecraft, by trend prediction of the course of a time-dependent series of data points determined at the component or system by measuring, the method comprising: providing an optimised decision tree, the input node of which is provided for inputting an input vector, the nodes of which contain the attributes of the respective input vector and the leaves of which each contain an extrapolation function provided for trend prediction; iteratively calculating future data points by an input vector being derived from a time-dependent series of data points and the decision tree calculating a data point subsequent to the last data point of the time-dependent series of data points from the input vector in an automated manner, the calculated subsequent data point being added to the time-dependent series of data points in order to be used for forming a new input vector for the next iteration step.