PLACE OF NIGHT WORK IN INDUSTRY 7 
In most plants where the rotating system is utilized, night 
work is a necessity. In the continuous industries night work 
in almost all plants is on a rotating basis. In relatively few 
cases is a rotating plan used where night work is only tempo- 
rarily utilized. The reasons for this are apparent since, in 
order to operate a rotating plan, the groups of workers on 
the various shifts must be organized as complete, equal 
units, which is rarely possible with temporary night work. 
Under these circumstances, in almost all establishments 
where night work is only a temporary expedient, a temporary 
fixed plan is used, the employees being definitely assigned to 
specified hours of work. 
The degree of efficiency of night forces was found to vary 
according to the plan of night work organization used. For 
the purpose of this study the plants which submitted the 
necessary data to the Conference Board are classified in three 
groups according to the type of shift employed. A classifica- 
tion on this basis shows that of the 250 plants which furnished 
data on this item, 113 plants are on a regular rotating basis, 
85 establishments operate on a fixed regular basis, and 52 
plants are on a fixed temporary basis.! 
PrororTION OF EMPLOYEES ON NIGHT WORK 
In order to determine the proportion of employees engaged 
in night work to the total number of workers, plants where 
night work is regularly utilized and those where it is only 
temporarily organized were separated. The results of this 
classification are presented in Table 1 for companies which 
reported the total number of employees and the number on 
night work within a 24-hour period. 
An analysis of the table shows that in industries which 
operate continuously the rotating shift plan of night work 
organization predominates. A noteworthy exception is the 
telephone and telegraph industry, which utilizes a compara- 
tively small night force, organized on a regular fixed shift 
plan. In industries which employ night forces regularly or 
at certain intervals of the year, for example, in the rubber 
1 In seven instances some of the company plants employed different plans of 
aight work organization.