Time Study

Time study is a structured process of directly observing and measuring human work using a timing device to establish the time required for completion of the work by a qualified worker when working at a defined level of performance.

It follows the basic procedure of systematic work measurement of:

• analysis of the work into small, easily-measurable components or elements
• measurement of those components and
• synthesis from those measured components to arrive at a time for the complete job.

The observer first undertakes preliminary observation of the work (a pilot study) to identify suitable elements which can be clearly recognised on subsequent occasions and are of convenient length for measurement.

Subsequent studies are taken during which the observer times each occurrence of each element using a stopwatch or other timing device while at the same time making an assessment of the worker's rate of working on an agreed rating scale. One of the prime reasons for measuring elements of work, rather than the work as a whole is to facilitate the process of rating. The rate at which a worker works will vary over time; if elements are carefully selected, the rate of working should be consistent for the relatively short duration of the element. More information on rating is given within the entry on work measurement. This assessment of rating is later used to convert the observed time for the element into a basic time; a process referred to as "extension". It is essential that a time study observer has been properly trained in the technique and especially in rating.

Time study, when properly undertaken, involves the use of specific control mechanisms to ensure that timing errors are within acceptable limits. Increasingly, timing is by electronic devices rather than by mechanical stopwatch; some of these devices also assist in subsequent stages of the study by carrying out the process of "extending" or converting observed times into basic times. The basic time is the time the element would take if performed at a specified standard rating.

The number of cycles that should be observed depends on the variability in the work and the level of accuracy required. Since time study is essentially a sampling technique in which the value of the time required for the job is based on the observed times for a sample of observations, it is possible using statistical techniques to estimate the number of observations required under specific conditions. This total number of observations should be taken over a range of conditions where these are variable and, where possible, on a range of workers.

Once a basic time for each element has been determined, allowances are added (for example, to allow the worker to recovere from the physical and mental effects of carrying out the work) to derive a standard time.

Time study is a very flexible technique, suitable for a wide range of work performed under a wide range of conditions, although it is difficult to time jobs with very short cycle times (of a few seconds). Because it is a direct observation technique, it takes account of specific and special conditions but it does rely on the use of the subjective process of rating. However, if properly carried out it produces consistent results and it is widely used. Additionally, the use of electronic data capture devices and personal computers for analysis makes it much more cost effective than previously.