For example, this year's accident 10, with a total working time of 200,000. Take a constant, c = 200,000.
This year's accident operation index, Z 1 =[ total number of accidents this year (10) XC (200000)] ÷ total working hours this year (200000)= 10, the safety management index is definitely going down, so the index for next year is z2 =/.
At the conclusion of the next year, the formula Z3 =[ total number of accidents in the next year (10) XC (200000)] ÷ total working hours in the next year (200000) can be applied continuously. If Z3≤Z2, the safety management is effective, otherwise it can be reviewed.
This indicator can be used to count the monthly running value and cumulative running value, and if a month exceeds the standard, the management means can be adjusted in time.
Subscript can't be used, make do with it, typing is very hard, give points.