Work measurement is a foundational practice in industrial engineering and operations management, representing a systematic way of determining the time needed to perform a task. Quantifying work content is a direct path to understanding and improving operational efficiency and productivity. By objectively analyzing the time component of any job, an organization gains the necessary data to standardize performance expectations and make informed decisions about resource allocation. This discipline provides a clear, data-driven framework for managing the time expenditure associated with production and service processes.
Defining Work Measurement and Its Core Purpose
Work measurement is the application of techniques designed to establish the time required for a qualified worker to carry out a specified task at a defined level of performance. The goal of this systematic analysis is to determine the “Standard Time,” which is the total time allotted for a task, including allowances for personal needs, fatigue, and unavoidable delays.
A qualified worker possesses the necessary attributes, skill, and knowledge to perform the job safely and effectively. The pace of work is normalized to a standard rating, ensuring the time standard reflects what an average, trained, and motivated worker can sustain over an entire shift. The core purpose is to establish an objective benchmark of human effort and time expenditure, eliminating ineffective time that does not contribute to the final output.
Distinguishing Work Measurement from Methods Study
Work measurement and methods study are often grouped under the umbrella of “Work Study,” but they serve distinct and sequential functions. Methods study, or motion study, focuses on optimizing the procedure—the “how” of a task—by systematically recording and examining ways of doing work to develop an easier and more effective method. This precedes time quantification because measuring the time for a known inefficient process is unproductive.
Work measurement, in contrast, focuses on the time—the “how long” of a task—by applying various techniques to establish the standard time for the already-optimized method. For example, method study is the process of a mechanic figuring out the most efficient sequence of steps and tools to replace a part. Work measurement is the subsequent process of timing that refined sequence to determine how long the replacement should take a trained mechanic.
Key Techniques Used to Measure Work
Time Study
Time study is a direct observation technique that involves using a stopwatch to record the time taken for a qualified worker to complete the elements of a task. The analyst breaks the job into small, measurable elements and records the observed time for each element over several cycles. Because the observed worker’s pace may differ from the average, the analyst applies a performance rating factor to the observed time to calculate the Normal Time. This Normal Time is then adjusted by adding allowances—to compensate for factors like personal needs, fatigue, and minor unavoidable delays—to arrive at the final Standard Time.
Work Sampling
Work sampling is a statistical technique used to determine the proportion of a worker’s or machine’s time spent on various activities through random observations. Instead of continuous observation, an analyst takes a large number of instantaneous “snapshots” of the activity at random intervals over an extended period. The percentage of observations where a worker is engaged in a specific activity, such as working, waiting, or idle, is a statistically sound estimate of the total time spent. This method is useful for measuring long-cycle, non-repetitive work or the activities of a group of workers, as it is less intrusive and more cost-effective than continuous time study.
Predetermined Motion Time Systems (PMTS)
Predetermined Motion Time Systems (PMTS) bypass the need for direct observation and stopwatch timing by utilizing a database of established time values for basic human motions. These systems, like Methods-Time Measurement (MTM), analyze a task by breaking it down into fundamental motions such as reach, grasp, move, and release. A standard time value, often expressed in Time Measurement Units (TMU), is assigned to each motion based on variables like distance and object weight. The standard time for the entire task is synthesized by summing the time values for all the constituent motions, which is valuable for setting standards before a job enters production.
Standard Data and Formulae
The Standard Data method involves compiling and reusing previously measured time values from time studies or PMTS analyses for elements common to various jobs. This data, often organized into tables and formulae, allows an analyst to build the standard time for a new task without conducting a redundant or time-consuming new measurement. For instance, if the time to “tighten a specific bolt with a specific wrench” has been accurately measured and documented, that elemental time can be applied to any new job requiring the same motion. This synthesis approach accelerates the standard-setting process for jobs that share common work elements.
Practical Applications and Benefits for Organizations
The establishment of accurate standard times through work measurement yields operational and financial advantages for any organization. Standard times serve as the foundation for accurate labor cost calculation, allowing management to precisely determine the direct labor cost component per unit of product or service. This precision is utilized in standard costing systems, where the difference between the standard labor cost and the actual labor cost exposes inefficiencies and allows for budgetary control. Knowing the time content of work enables accurate forecasting and financial planning.
Standard time data is also used for production planning and scheduling, providing a reliable basis for estimating total workload and determining delivery dates. In an assembly line environment, standard times are applied to balancing the production line. This is achieved by distributing tasks among workstations so the work time at each station is nearly equal, which eliminates bottlenecks, minimizes idle time, and maximizes throughput. These objective standards provide a fair basis for setting performance goals, establishing incentive wage systems, and making data-driven decisions about staffing levels and resource allocation.
Steps for Implementing a Work Measurement Study
A formal work measurement study follows a structured, sequential process, regardless of the specific technique chosen. The initial step involves selecting the job or task to be studied and defining the scope of the measurement. Next, the analyst must ensure the method for performing the job is standardized and recorded in detail, confirming that any prior method study work has been implemented. Only after the method is finalized can the measurement phase begin, where the appropriate technique is used to measure the time taken to perform the work elements.
The collected data is used to calculate the Normal Time by adjusting the observed time with a performance rating factor. The analyst then determines the necessary allowances for personal time, fatigue, and contingencies, adding them to the Normal Time to calculate the final Standard Time for the task. The final phase involves applying the established standard by integrating it into scheduling, costing, and incentive systems, and instituting a system for maintaining the standard through periodic checks and updates.