grade differential meaning in English

等级差别

Secondly , the thesis bring ups to make use of mathematics clustering analysis method , combine with analysis the accident occur rate of each occupation ( business enterprise ) , the death rate of employment injury , the severely wounded rate of employment injury , the slight wound rate of employment injury , the death rate of occupational disease , the occur rate of occupational disease and the circumstance of employment injury overhead and so on , to classify the risk grades of occupation ( enterprise ) . according to the clustering consequence , the grade differential rate of the
其次，论文运用数学聚类分析方法，结合各行业（企业）的事故发生率、工伤死亡率、工伤重伤率、工伤轻伤率、职业病死亡率、职业病病伤率以及工伤费用支出情况等指标进行行业（企业）风险等级分类。根据分类结果，合理确定各行业风险等级差别费率。再次，论文通过对国内外现行工伤保险费率浮动方法的研究，提出了结合企业千人死亡率、千人重伤率、千人轻伤率和支收率指标来确定企业费率浮动的方法。