work measurement

an aspect of WORK STUDY which involves the application of measurement techniques to establish the time it takes for a trained worker to carry out a particular JOB. The purpose of measuring the time required to complete a job is to provide management with information for PRODUCTION SCHEDULES, for PRODUCT COSTING, and to assist in the design of incentive payment systems such as PIECEWORK.

Timestudy is the most often used work measurement technique for recording the time it should take to complete a specified job. Time study involves a number of steps:

Recording details of the job and checking that no obvious improvements in method can be made (see METHOD STUDY);
Dividing up the job being done into discrete operational elements to facilitate the timing of each component element;
Timing the work elements to obtain the observed time;
Rating the performance of the worker by comparing his or her actual rate of working against the defined STANDARD RATE (the average rate of working of a skilled, motivated operative) and using this to adjust the observed time and arrive at the basic time;
Determining the percentage allowances to be added to the basic time to compensate for fatigue, contingencies like machine breakdowns and interruptions, in order to establish the standard time for the job.

Time study is appropriate for short-cycle repetitive work. If, however, it is necessary to establish work standards in situations where irregular long-cycle work is conducted or where many different jobs are performed, these techniques may well be quite inappropriate. In such circumstances it may well be advisable to use some form of activity sampling, which in its simplest form consists of visual sampling and recording of activities in order to establish the proportion of time in which employees or machines are working or idle (see ACTIVITY CHART).

Time study is a direct work measurement technique. Alternatively, various indirect measures may be employed to generate standard times. One method uses data collected from previous time studies to provide a synthetic standard time for a job which differs only marginally from a job which has already been subject to direct time study or a new job which has not yet begun. A second method, the predetermined motion time system lists all motions that workers can utilize in performing tasks, together with times for these motions. From this general list of motions it is possible to select the specific motions involved in a particular job and thus compile a standard time for this particular job. Finally, analytical estimating can be used where there is insufficient synthetic data available to allow time standards to be established for all job elements and where the time required for these elements has to be based on knowledge and practical experience. See SIMULTANEOUS MOTION CHART, THERBLIGS.