Work Measurement

It is the determination of the degree and quantity of labor in performing tasks. It is actual quantifying of performance dimensions. Managers are used to measuring work in terms of “hours of work done”. In many cases, this provides very inaccurate data on performance. With performance measurements which depend on establishing standards, we can determine how well a process is proceeding to forecast the end conditions. The fundamental purpose of work measurement is to set time standards for work. Standards are needed for several reasons: One reason is the need to measure performance, which requires a comparison of accomplishment against a standard. Performance data is needed so that one can avoid surprises when one has to make decisions.

All scheduling requires some estimate of how much time it takes to do the work. Standards are necessary to schedule work and allocate capacity. Standards are used in industry as a basis for payments to workers where output based incentive plans employed. This requires an objective basis for motivating the workforce and measuring worker’s performance. Costing and monitoring of work presume the existence of standards. In contracting, this is particularly important for new contracts. Questions such as “Can we do it”? And “How best can we do it”? Can only be answered using standards. Most important, standards provide benchmarks for improvement. Using universal standard data, it is possible to compare your work standards with those of similar jobs in other organizations.

There are many techniques used to measure work. However, they can be classified into those that rely either on direct observation of the work or indirect observation of the work. Some techniques, such as motion-time systems or standard data can provide standard times from simulation, etc. However, the data on which such techniques are based, are based on earlier observations of actual work.

Work Measurement Techniques

There are six basic ways of establishing a time (work) standard:

• Ignoring formal work measurement
• Using the historical data approach’
• Using the direct time study approach
• Using the predetermined time study approach
• Using the work sampling approach
• Combining approaches 2 through 5

Ignoring Formal Work Measurement: For many jobs in many organizations, especially in the labor-intense service sector, formal labor standards are simply not set at all the issue of a fair day’s work for a fair day’s pay is ignored. Even though there is no explicit basis for criticism, workers may be blamed for poor performance and inefficiency. Often, because management has not established a work (time) standard, some informal standard is established by default. Since this informal standard generally compares unfavorably with those set by other techniques, we do not recommend ignoring formal work measurement.

Historical Data Approach: This method assumes that past performance is normal performance. In the absence of other formal techniques, some managers use part performance as their main guide in setting standards. What are the advantages of these methods? Basically, it is quick, simple, inexpensive, and probably better than ignoring formal work measurement altogether. The major disadvantage, as you can reason, is that past performance might not at all be what an average worker can reasonably be expected to perform under average working conditions.

Direct Time Study: Often called a time study, a stopwatch study, or clocking the job, this technique is certainly the most widely used method for establishing work standards in manufacturing. Perhaps you have observed a job being studied by an industrial engineer, clipboard and stopwatch in hand. How does direct time study work? Basically there are six steps in the procedure:

• Select the job to be timed: The direct time study approach depends upon direct observation and is therefore limited to jobs that already exist. The job selected should be standardized, in terms of equipment and materials, and the worker should be representative of all workers doing the job.
• Select a job cycle: Identify the elements and tasks that constitute a complete cycle. Decided how many cycles you want to time with a stopwatch.
• Time the job for all cycles and rate the worker: Workers behave in varying ways when their performances are being recorded; common reactions are resentments, nervousness, and slowing the work space. To minimize these effects, repeated study, study across several workers, and standing by one worker while studying a job somewhere nearby, perhaps in another department, can be helpful. You can assign the worker a rating, as a percentage of the “normal” or average worker. Industrial engineers frequently use a rating factor when timing jobs. In essence the engineer is judging the worker as 85 percent normal, 90 percent normal, or some other rating depending on his or her perception of “normal.” Obviously, ratings of this kind depend on subjective judgments. Compute the normal time based on the average cycle time and the worker rating. Determine the fraction of time available, making allowances for personal needs; delays, and fatigue, Set the performance standard (standard time) based on the normal time and the allowances.

To be more precise about the calculations of this procedure:

Sum of cycle times recorded

Average cycle time                  =         ——————————–

Number of cycles observed

Normal time                           =        Average cycle time x Worker rating

Allowance fraction                 =          Fraction of time for personal needs, fatigue, and unavoidable delays

Available fraction of time        =          1- Allowance faction

Normal time

Standard time                         =          ————————–

Available fraction of time

Predetermined Time Study: For setting standards for jobs that are not currently being performed but are being planned, the predetermined time study is helpful. A predetermined time study can also be applied to existing jobs as an alternative to a direct time study. The bases of this technique are the stopwatch time study and time study from films. Historical data have been accumulated on tens of thousands of people making such basic motions as reaching, grasping, stepping, lifting, and standing. These motions have been broken down into elements, each element timed, the times averaged to yield predetermined time standards, and the standards published in table form. The procedure for setting a predetermined time standard is as follows:

• Observe the job or think it through if it is not yet being performed: It is best to observe under “typical” conditions: typical machine, materials, and worker.
• Itemize the job element: Do not be concerned about timing them; just thoroughly document all the motions performed by the worker.
• From a table of predetermined time standards, record the standard for each motion units: Motion units are expressed in some basic scale (a The rblig scale is often used) that corresponds to time units.
• Find the sum of the standards for all motions.
• Estimate an allowance for personal time, delays, and fatigue, and to the sum of standards. This total sum is the predetermined time standard for the job.

The primary advantage of predetermined time studies is that they are not skewed by a typical performance of workers who are nervous because they are being timed: the timing has already taken place – away from the workplace in a logical, systematic manner. The basic disadvantage of this technique is that some job elements may not be recorded, or may be recorded improperly. Furthermore, if job elements can’t be properly categorized and located in a table, a direct time study approach must be made instead of the predetermined time study.

Work sampling: Work sampling does not involve stopwatch measurement, as do many of the other techniques; instead, it is based on simple random sampling techniques derived from statistical sampling theory. The purpose of the sampling is to estimate what proportion of a worker’s time is devoted to work activities. It proceeds along the following steps:

• Decide what activities are defined as “working.” “Not working” comprises all activities not specifically defined as “working.”
• Observe the worker at selected intervals, recording whether a person is working or not.
• Calculate the portion P of time a worker is working as :

Number of observations during which working occurred

P = ——————————————————

Total number of observations

This calculation can then be used as a performance standard.

Work sampling can also be used to set standards; the procedure is similar to the one used in direct time studies.

Work sampling is particularly adaptive to service to service sector jobs such as those in libraries, banking, health, banking, health care, insurance companies, and government. Accuracy of this technique depends keenly upon sample size.

Disadvantages of work sampling are that the analyst may not be completely objective or may study only a few workers, and that “working” is a broad concept not easily defined with precision. There are, however, some obvious, advantages with work sampling: It is simple easily adapted to service sector and indirect labor jobs, and an economical way to measure performance. In short, work sampling is a useful work measurement technique if it is used with discretion.

Combining Work Measurement: Techniques which work measurement technique should you use? In practice, they are used in combination, as cross-checks. One common practice is to observe a job, write down in detail all the job elements, and set a predetermined time standard. Then you can check the history of performance on this or similar jobs to verify that the predetermined standard is reasonable. To provide a further check, a direct time study can be made of the job by element and in total. No one work measurement technique is totally reliable. Because of the high skill level required in setting the standard, a cross-check is desirable whenever possible.