Stopwatch Time Study makes direct observations by means of a simple stopwatch measuring, generally, to the precision of 0.01 minute. The observation equipment consists of the stopwatch, the recording board, the observation sheet and a pencil. The steps involved in such a study are:
1. Subdivide the job into observable and distinct elements.
2. Choose acceptable operator/s for study
3. Make direct observations of the work elements while the operator is actually performing the job and record the time of each element. Make a statistically adequate number of repeated measurements and record the time of each element. Make a statistically adequate number of repeated measurements and record each time.
4. Performance rate each element and record
5. Calculate the normal time.
6. Establish allowances
7. Compute the standard time.
The key step in stopwatch time study is that of subdividing the job into component elements. One should take care that the elements are distinct or well defined and therefore amenable to repeated measurements. Also, the elements should be as short as possible without losing accuracy of measurement; the practical minimum is generally 0.02 or 0.03 minute the time required to read and record being 0.027 minutes or 45 TMU (Time measurement Unit) The following are uses of this breakdown into elements:
1. It helps in separate performance rating of each of the job elements, instead of performance rating the whole job (which may lead to much error in the Time Standard).
2. If a job method changes in terms of only one or two elements, the revised time standard can be easily established in the future, unnecessary time studies are, therefore, eliminated. Standards for similar or related jobs can also be easily established.
3. It highlights the work element which consumes excessive time, and this can then be subjected to a critical examination to eliminate/ substitute the element.
4. Element/s with large variation in time can be examined for necessary changes in the job design or method.
5. It highlights the inconsistency in working conditions.
6. Such division into elements provides a detailed method description which can be used for training new workers.
A few points may be mentioned regarding elementalization:
1. One must separate the machine time from the worker time. At certain times the worker may appear to be working slow, but in actuality he may be waiting for a machine element to complete. Obviously, the worker cannot be performance rated low for this element.
2. While studying a job, elements of work other than the usual cycle may be encountered frequently. For instance, once in every 10 cycles the operator may clean the tool; or once in every 40 cycles the operator may have to place the tray filled with finished work pieces with an empty tray; or he may get the raw material once a few cycles. These elements have got to be included in the time analysis since that are integral part of the work. But since these elements are outside the routine cycle, they are called foreign elements. There may be some genuine foreign elements such as when the worker is talking to a fellow employee or some other interruption which is not a part of the work. The Work Study analysts must note all the foreign elements as and when they occur.
3. It may also help if the analyst separates the constant elements from the variable elements.
4. Also, there is no unique method of subdividing a job into elements. Much depends upon the particular job being studied, the type of jobs encountered in the plant, and finally the judgment of the analysts. Only the precautions of distinctiveness and appropriate shortness of elements and of differentiating between constant variable elements and man-or-machine elements needs to be observed.
For the Time Study one has to choose an acceptable operator. He is one amongst many operators who are trained sufficiently in the job to be performed and are healthy and skilled or capable of performing the job at an acceptable pace day in and day out. He is not an abnormally fast or slow worker but one amongst the many who fall in between who might qualify for dong the job. The theme is to:
1. eliminate the extraordinary (in either sense) and
2. to time study only those jobs that have received sufficient learning or training (reaching saturation in terms of learning) and in general all the working conditions are well established/settled.