In proficiency testing activities

to the problems of inaccurate classification caused by robust statistical methods

a vertical segment of the evaluation criteria is designed using kernel density estimation function. With the raw data measured in the laboratory

using kernel density function estimated the density function of the data obeyed

and then calculated the corresponding function value of the measured value

by the function value of the size

to achieve the effect of classification.The results show that this method increases the degree of satisfaction of the measurement results

makes up the lack of robust statistical method only to classify the normal data and expends the scope of data classification.