work measurement

work measurement

[′wərk ‚mezh·ər·mənt]

(industrial engineering)

Determination of the difficulty of a given task by using both physiologic and biomechanical parameters to evaluate compatibility of available motions with motions required to perform the task.

ergonometrics

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

Work measurement

The determination of a set of parameters associated with a task. There are four reasons, common to most organizations whether profit seeking or not, why time, effort, and money are spent to measure the amount of time a job takes. These are cost accounting, evaluation of alternatives, acceptable day's work, and scheduling. The fifth, pay by results, is used only by a minority of organizations.

There are three common ways to determine time per job: stopwatch time study (sequential observations), occurrence sampling (nonsequential observations), and standard data.

Three levels of detail for standard time systems

Micro system (typical component time range from 0.01 to 1 s; MTM
nomenclature)
Element	Code	Time
Reach	R10C	12.9 TMU*
Grasp	G4B	9.1
Move	M10B	12.2
Position	P1SE	5.6
Release	RL1	2.0
Elemental system (typical component time range from 1 to 1000 s)
Element		Time
Get equipment		1.5 min
Polish shoes		3.5
Put equipment away		2.0
Macro system (typical component times vary upward from 1000 s)
Element		Time
Load truck		2.5 h
Drive truck 200 km		4.0
Unload truck		3.4
*27.8 TMU = 1 s; 1 s = 0.036 TMU. source: S. A. Konz, Work Design, published by Grid, 4666 Indianola Avenue, Columbus, OH 43214, 1979.

Stopwatch time study can be used for almost any existing job. It is reasonable in cost and gives reasonable accuracy. However, it does require the worker to be rated. Once the initial cost of standard data system has been incurred, standard data may be the lowest-cost, most accurate, and most accepted technique.

Occurrence sampling is also called work sampling or ratio-delay sampling. If time study is a “movie,” then occurrence sampling is a “series of snapshots.” The primary advantage of this approach may be that occurrence sampling standards are obtained from data gathered over a relatively long time period, so the sample is likely to be representative of the universe. That is, the time from the study is likely to be representative of the long-run performance of the worker.

Reuse of previous times (standard data) is an alternative to measuring new times for an operation. There are three levels of detail: micro, elemental, and macro (see table). Micro-level systems have times of the smallest component ranging from about 0.01 to 1 s. Components usually come from a predetermined time system such as methods-time-measurement (MTM) or Work-Factor. Elemental level systems have the time of the smallest component, ranging from about 1 to 1000 s. Components come from time study or micro-level combinations. Macro-level systems have times ranging upward from about 1000 s. Components come from elemental-level combinations, from time studies, and from occurrence sampling. See Methods engineering, Performance rating, Productivity

McGraw-Hill Concise Encyclopedia of Engineering. © 2002 by The McGraw-Hill Companies, Inc.