A turbo machine, a computer-implemented method, and a computer system for operating a compressor assembly are provided. The method includes comparing a first data set and a second data set to determine a first correlation factor, comparing the first correlation factor to a first threshold that at least partially determines whether a stall precursor exists, removing mean values from the first data set and the second data set, comparing the first data set and the second data set each removed of mean values to determine a second correlation factor, and comparing the second correlation factor to the first threshold, and classifying the stall precursor as either a spike stall precursor, a modal stall precursor, or a combination stall precursor.