A time standard for a job or an operation may be established by time study, by work sampling, or by the use of predetermined times.
Predetermined time standards (PTS) are advanced techniques which aim at defining the time needed for the performance of various operations by derivation from preset standards of time for various motions and not by direct observation and measurement. They are not normally considered suitable for the trainee to use until he has gained a real understanding of and considerable experience in work study practice.
A predetermined time standard is a work measurement technique whereby times established for basic human motions classified according to the nature of the motion and the conditions under which it is made is used to build up the time for a job at a defined level of performance.
Factors to be considered in using a Predetermined Time System
1. The application of PTS requires that the operation being measured be divided into basic motions.
2. At the time a PTS is first adopted by a company the level of performance as represented by the time standards produced by the system should be determined and adjustment made, if necessary, in order to match the company performance level.
3. Most pre-determined time systems do not include allowances so these are added as they would be in a time study.
Advantages of pre-determined time systems
PTS systems offer a number of advantages over stop watch time study
1. With PTS one time is indicated for a given motion, irrespective of where such a motion is performed. In stop watch study it is not so much as a sequence of motions making up an operation is timed.
2. Timing by direct observation and rating can sometimes lead to inconsistency. A PT system avoids both rating and direct observation and hence can lead to more consistency in setting standard times.
3. Since the times for the various operations can be derived from standard time tables, it is possible to define the standard time for a given operation even before production begins and often while the process is still at the desi0gn stage. This allows the work study man to change the layout and design of the workplace and of the necessary jigs and fixtures in such a way that the optimum production time is achieved.
4. It is also possible before starting the operation to draw up an estimate of the cost of production, and this could be valuable for budgeting.
To summarize they are not too difficult to apply and can be less time consuming than other methods when time standards are determined. They are particularly useful for very short repetitive time cycles such as assembly work in the electronics industry.