Abstract: Provided are a system and method for condition based maintenance of electrical devices. In one example, the method includes receiving test data that represents an attribute of a tested electrical device. The received test data is classified as belonging to a client and added to a control set representing an aggregate of information from many clients. The received test data is processed using a sparse data process if the attribute is represented by two sets of test data, and is processed using an autoregressive process if the attribute is represented by three or more sets of test data. Both the sparse data process and the autoregressive process may use information from the client and the control set. A future value of the attribute is predicted based on the processing, and at least a representation of the future value is output.