A multiple activity chart records the related sequence of activities of more than one subject, men and / or machine on a common time scale showing the relationship between them. By recording their activities separately , it is possible to depict on the chart the periods of working and non working on the part of any of the subjects during a cycle of the process. A study of the chart would bring to light the activity interference or the ineffective utilization of men and/ or machine and action can be taken to rearrange the activities to eliminate or reduce the idleness or ineffective time.
The activities of different workers and machines are recorded against a common time scale in sequence in terms of working time and idle time by drawing respective bars. These timings can be observed by an ordinary wristwatch or a stopwatch according to the accuracy required and the duration of each activity. Timings can also be built up from previous measurements.
The inactive activity is left blank, whereas the active one is normally shaded. Sometimes the followings shadings are also used to represent each activity.