SECTION 3 
ACCIDENTS IN TERMS OF PRODUCTION 
THE basis upon which the accident frequency and severity rates have 
been calculated elsewhere in this report is the man-hours worked. 
Such rates are usually accepted as the most satisfactory measures of 
general hazards and furnish the best guide for accident-prevention 
efforts. Another basis upon which accident rates may be calculated 
is the quantity of production. There are some instances where acci- 
dent rates in terms of production may be used to advantage as an 
adjunct to rates in terms of man-hours. 
The accident frequency and severity rates have been determined in 
terms of production for 24 industrial groups. The trends for each 
group are shown in the accompanying Charts 40 to 63, inclusive. 
By the least-square method the increases or decreases for each rate 
have been calculated. These percentages appear in Table III. The 
accident frequency and severity rates when expressed in terms of 
production have, with a few exceptions, decreased during the period 
considered. In considering accident rates in terms of production, it is 
essential to bear in mind that those of different industrial groups can- 
not be combined. Furthermore, the rates are influenced by any one 
of the following conditions: reduced number of accidents during a 
period when the quantity of production remained stationary; the 
aumber of accidents stationary during a period when the quantity 
of production increased; the number of accidents reduced during a 
period when the quantity of production increased; and the number of 
accidents reduced at a more rapid rate than the quantity of produc- 
tion decreased. 
All other things being equal, greatest reduction in accident rates, 
expressed in terms of production, will take place when the number 
of accidents is decreased simultaneously with an increase in the quan- 
tity of production. Accident frequency and severity rates in terms 
of production were derived for 25 industrial groups; the per cent 
of increase or decrease of each rate was determined by the least-square 
method for the period involved in each instance. The basic data 
and the’ results of the computations are shown in Table III. In the 
majority of the groups of Table III an increase in the quantity of 
production occurred simultaneously with a decrease in the number of 
accidents, therefore two favorable conditions obtained which resulted 
in large reductions in accident frequency and severity rates when ex- 
pressed in terms of production. Such favorable conditions prevailed 
in the industries listed on page 84. 
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