What is Work Measurement? Benefits, Process, Techniques

What is Work Measurement?

Work measurement is the process of applying methods for determining the content of a job. Job content can only be measured if the method for performing it is standardised, which is done through a method study. According to BSI, work measurement is “the application of techniques designed to establish the time for a qualified worker to carry out a specified job at a defined level of acceptance.” In simpler words, work measurement is a method used to determine the time required to perform a job by a qualified worker.

The time taken to perform a job is known by various terms, including the time standard, work standard, labour standard, production standard or standard time. The standard time is expressed in minutes per unit of output or unit of output per hour. Work measurement enables an organisation to plan and control its operations.

Unless the work content is measured, it is difficult to identify the capacity level of a production plant. Work measurement is also used for introducing incentive schemes and standard costs for budget control. It also helps organisations to achieve a high level of labour productivity.

The major objectives of work measurement are as follows:

• To improve the planning and controlling of operations
• To make work handling more effective
• To provide indices to measure labour performance
• To enable an organisation to control its labour cost
• To improve incentive schemes

---

Benefits of Work Measurement

As discussed earlier, work measurement assists the planning and control of various jobs in an organisation. Apart from this, there are several other benefits of work measurement:

• It can compare alternative methods developed in a method study.
  
  
• It is used to prepare a work schedule by assessing the work done by workers.
  
  
• It is used to establish standards for measuring the efficiency of labour.
  
  
• It compares the time taken by labour to perform a job.
  
  
• It facilitates the estimation of labour cost.
  
  
• It provides data with respect to the approximation of tenders, fixation of selling price and assessment of delivery schedule.

---

Process of Work Measurement

The process of work measurement involves the following steps:

• Dividing the work into elements
  
  
• Recording the time taken by each element to perform its work with the help of work measurement techniques, such as time study, the synthesis method and analytical estimating
  
  
• Defining a standard time for each element by extending the observed time to normal time by applying a rating method
  
  
• Evaluating the relaxation allowance for personal requirements and physical and mental fatigue
  
  
• Including the relaxation allowance in the normal time for every element to determine the work content
  
  
• Identifying the repetition of an element in a job, multiplying the work content with a number of times the element is repeated, and adding the time taken to determine the actual work content of a job
  
  
• Including the contingency allowance in the determined work content

---

Techniques of Work Measurement

Work measurement uses various techniques to determine the work content of a job. Figure lists some of the most commonly used work measurement techniques:

Let us discuss each of these techniques in detail.

Time Study

Time study is used to determine the standard time required to perform a job. According to ILO, “time study is a work measurement technique for recording the times and rates of working for the elements of a specified job carried out under specified conditions and for analysing the data so as to obtain the time necessary for carrying out the job at a defined level of performance.”

Some of the objectives of time study are as follows:

• To identify the time required by an individual to do a job
• To establish a basis for comparing operational effectiveness
• To compare different work methods for choosing the best method
• To determine the standard cost
• To provide a basis for setting incentive wages
• To establish the completion schedules for individual operations

Time study is generally performed with the help of a stop watch, which can be started or stopped instantaneously. Therefore, it helps to measure accurately the time taken to complete a job. Figure illustrates the process of time study conducted through a stop watch:

Let’s consider each step in detail:

• Select a job that needs to be studied: Select a job based on the following factors:
  
  
  • New job in production
    
    
  • Change in the method used for performing a job
    
    
  • Change in resources, such as materials and machines, used for performing a job
    
    
  • High labour cost
    
    
  • Established standard time for performing a job
    
    
• Select a worker who needs to be studied: In this step, a qualified worker is chosen for establishing the standard time for performing a job. A qualified worker has all the required skills, intelligence, and physical attributes to perform a job, while meeting the standards of quality, quantity and safety.
  
  However, it is difficult to find an individual who has all these qualities. Therefore, the organisation chooses the best available worker and calculates the time taken by him/her to complete a job.
  
  
• Calculate the time taken for performing a job, using a stop watch: In this step, the organisation determines the time taken to perform a job by using the following sub-steps:
  
  
  • Collect all information related to the job, worker and working conditions.
    
    
  • Record the work method used for performing a job.
    
    
  • Split the job into different elements. An element can be of the following types:
    
    
    • Repetitive Element: This element occurs in every cycle of the job.
      
      
    • Occasional Element: This element occurs after a regular interval of time.
      
      
    • Constant Element: This element’s normal time remains the same.
      
      
    • Variable Element: This element’s normal time varies.
      
      
    • Manual Element: This element is performed manually.
      
      
    • Machine Element: This element is performed with the help of machines.
      
      
    • Governing Element: This element requires more time to perform as compared to the other elements.
      
      
    • Foreign Element: This is an unnecessary element of a job.
      
      
• Analyse the different elements of a job. This helps to determine the most effective work method for performing the job.
  
  
• Record the time taken by the qualified worker to perform each element of the job with the help of a stop watch.
  
  
• Determine the rating factor/scale by comparing the actual speed of the worker with the standard speed of performing a job. The qualified worker is assumed to have a standard speed. The formula to calculate the rating factor/scale is as follows:
  
  The rating scale can be of three types:
  
  
  • 60-80 scale
  • 75-100 scale
  • 100-133 scale (1/3 scale)
    
    
• Calculate the normal time taken by a worker to perform a job. After selecting the rating scale and calculating the rating factor, the normal time of the worker is calculated using the following formula:
  
  
  Normal time = Observed time * Rating factor
  
  
• Calculate the observed time. To do so, record the time taken for performing the activities of an element. Repeat this action depending on the number of work cycles and their length. The formula to calculate the average observed time is as follows:
  
  
  Average observed time = Sum of element times/Number of cycles
  
  
• Identify the time allowances given to the worker while performing the job. To calculate these allowances, you use a percentage of normal time. There are three types of allowances:
  
  
  • Relaxation Allowance (RA): This allowance is provided to a worker to avoid fatigue, which could be due to physical exertion, posture, working conditions and personal needs. RA varies from 10 to 20 percent of normal time and is also known as Personal Fatigue on Delay (PFD) allowance.
    
    
  • Contingency Allowance (CA): This allowance is provided for non-repetitive activities, such as getting materials from retail stores, polishing of tools, and consultation from a supervisor. CA is about 5 percent of normal time.
    
    
  • Process Allowance: This allowance is provided to a worker for his/her idleness, which is the result of the production process. For example, workers employed on an automated machine get process allowance.
    
    
• Finally, calculate the standard time by adding related allowances to normal time. Therefore, the formula to calculate the standard time is as follows:
  
  Standard Time = Normal – Time + Relevant – Allowances
  

Synthesis Method

The synthesis method determines the standard time to perform a job using either the previous time studies conducted on similar jobs with the same elements or with the standard data. Standard data includes normal time values for different elements. It is prepared by integrating the time of different standard elements.

A catalogue of standard data can be prepared for different elements. In the synthesis method, the elements of the job to be studied are determined. After that, the time taken to perform these elements is identified from the catalogue of standard data. Further, the time values of different elements of the job are added to determine the standard time to perform the job.

The benefits of the synthesis method are as follows:

• It reduces the cost and time involved in determining the standard time required by an element to complete its work.
  
  
• It helps in determining the labour time for preparing cost estimates for new jobs.

The synthesis method is used for the following applications:

• Determining the standard time for new jobs
• Estimating the production time to decide the price of products to be sold
• Aiding the preparation of incentive schemes

Analytical Estimating

Analytical estimating is one of the most important techniques of work measurement. It is used to determine the time values of jobs having long and non-repetitive operations. These time values are obtained from synthetic data or from the past experience of a work study engineer.

The process of analytical estimating involves a number of steps, which are as follows:

• Determining the job details, such as dimensions of a job and standard procedures and conditions for performing it
  
  
• Dividing the job into different elements
  
  
• Identifying the time values for as many elements as possible
  
  
• Assessing the time values for the remaining elements through past experience
  
  
• Adding the time values of all elements to get the total time
  
  
• Adding the relaxation allowance, which can range from 10% to 20% of the total time depending on the kind of job and its conditions
  
  
• Adding other allowances if applicable to obtain the standard time for performing a job

Predetermined Motion Time System

The Predetermined Motion Time System (PMTS) technique is used to establish the normal time for basic human motions. These time values are used to determine the standard time for performing a job. The standard time determined through PMTS is considered to be the standard data for a number of human body motions, such as moving, reaching, and positioning, which are common in several industrial operations.

There are three types of PMTS:

Methods Time Measurement (MTM)

MTM is the PMTS in which time values for basic human body motions are expressed as Time Measurement Units (TMUs). MTM can be applied to a number of operations, including:

• Formulating effective work methods before the initiation of the production cycle
• Refining the existing work methods
• Preparing the standard time data
• Determining the labour cost and time involved in performing a job

Work Factor

Work factor is the PMTS that classifies basic body movements in terms of arm and finger movements. These movements may take longer due to resistance from certain factors, such as weight, change of direction and manual control, which slows down the work process. These factors are known as work factors.

Basic Motion Time (BMT)

BMT is the PMTS used to determine time values from labour experiments. These time values are tested against a variety of factory operations before standardising them. BMT data is based on basic body motions, such as finger, hand, arm, foot and leg movements.

These body motions are grouped into the following categories, based on the muscular control required to stop these motions:

• Class A Motions: These body motions can be stopped without muscular control.
• Class B Motions: These body motions require muscular control to be stopped.
• Class C Motions: These motions need muscular control to slow down or stop completely.

PMTS is considered an extension of motion study. It not only determines the best method but also identifies the standard time to perform a job. The method is regarded to be more economical than time study as well as an effective tool for measuring time of repetitive jobs having shorter duration.

Work Sampling

Work sampling is a technique in which samples of work of one or more employees are collected at regular intervals. These samples help in determining the amount of time required for performing a particular activity.

Work sampling helps an organisation in the following ways:

• It identifies the allowances to be included in the standard time.
• It indicates the type of work activities to be included in a work sample.
• It estimates the percentage of utilisation of groups of similar machines.
• It indicates the use of material handling equipment.
• It provides a basis for indirect labour time standards.
• It identifies the productive and non-productive use of clerical operations.
• It determines the standard time for repetitive operations.

The process of work sampling is as follows:

• Identify the study objectives.
  
  
• Prepare a plan for the sampling process, which involves the following activities:
  
  
  • Estimating the time required to complete every phase of the activity
    
    
  • Establishing the accuracy level
    
    
  • Estimating the required number of observations
    
    
  • Determining the period of study and scheduling the number of readings for this period
    
    
  • Establishing the method for observation, route to follow, and recording data
    
    
• Collect the data according to the defined method.
  
  
• Analyse the data and prepare the results. The number of observations required in work sampling can be determined as follows:
  
  σ_(p p ) ( = q n/ )
  
  n p = q p / _ [ ] σ ( ) ∧ 2
  
  Here:
  
  σ_(p )= Standard error of proportion
  p = Percentage of idle time
  q = Percentage of working time
  n = Number of observations