1. A method for determining a failure rate (PFH) of an electrochemical sensor type for a process, wherein the process is defined by determined values, or value intervals, (Para j , Para j ′) of a plurality of specified process parameters, and wherein a plurality of defect types (D i ) is specified for the sensor type, the method comprising the steps: assigning, by means of expert knowledge, a defect rate (R ij ) to each combination of one of the values, or value intervals, (Para j , Para j ′) of the specified process parameters and one of the specified defect types (D i ); and calculating the failure rate (PFH) of the sensor type according to a calculational specification with application of the defect rates (R ij ) to the combinations of a value, or value interval, (Para j , Para j ′) of a process parameter and a defect type (D i ).