Method and system for monitoring a fleet of assets

A computer-implemented method for identifying data anomalies in data obtained by a condition monitoring system from a fleet of industrial assets, wherein the condition monitoring system monitors a data stream associated with each asset in the fleet, wherein the data stream represents a condition of the asset, the method comprising:

• obtaining a first time series of data values for each asset in the fleet over a specified time period from the data stream associated with the asset;
• determining an average time series for the fleet based on the first time series for each asset;
• and
• for a selected asset in the fleet:
• generating a model of the dependency between the first time series for the selected asset and the average time series;
• generating a second time series for the selected asset, based on the model and the first time series;
• and
• identifying anomalous data values from the second time series.