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Copyright 2006 John Wiley & Sons, Inc.Beni AsllaniUniversity of Tennessee at ChattanoogaOperations Management - 5th EditionChapter 8 SupplementRoberta Russell & Bernard W. Taylor, IIIWork Measurement
Copyright 2006 John Wiley & Sons, Inc.
Copyright 2006 John Wiley & Sons, Inc.Supplement 8-*Lecture OutlineTime StudiesWork Sampling
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Copyright 2006 John Wiley & Sons, Inc.Supplement 8-*Work MeasurementDetermining how long it takes to do a jobGrowing importance in service sector
Services tend to be labor-intensiveService jobs are often repetitiveTime studies
Standard timeis time required by an average worker to perform a job onceincentive piece-rate wage system based on time study
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Copyright 2006 John Wiley & Sons, Inc.Supplement 8-*Stopwatch Time Study Basic StepsEstablish standard job methodBreak down job into elementsStudy jobRate workers performance (RF)Compute average time (t)
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Copyright 2006 John Wiley & Sons, Inc.Supplement 8-*Stopwatch Time Study Basic Steps (cont.)Compute normal time
Compute standard time
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Copyright 2006 John Wiley & Sons, Inc.Supplement 8-*Performing a Time Study
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Copyright 2006 John Wiley & Sons, Inc.Supplement 8-*Performing a Time Study (cont.)
Normal time = (Elemental average)(rating factor)Nt = ( t )(RF) = (0.053)(1.05) = 0.056Normal Cycle Time = NT = Nt = 0.387ST = (NT) (1 + AF) = (0.387)(1+0.15) = 0.445 min
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Copyright 2006 John Wiley & Sons, Inc.Supplement 8-*Performing a Time Study (cont.)Example 17.3
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Copyright 2006 John Wiley & Sons, Inc.Supplement 8-*
Number of CyclesTo determine sample size:
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Copyright 2006 John Wiley & Sons, Inc.Supplement 8-*
Number of Cycles: ExampleAverage cycle time = 0.361Computed standard deviation = 0.03Company wants to be 95% confident that computed time is within 5% of true average time
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Copyright 2006 John Wiley & Sons, Inc.Supplement 8-*Elemental Times FilesElemental standard time files
predetermined job element timesPredetermined motion times (for micro-motions)Time measurement units
TMUs = 0.0006 minute100,000 TMU = 1 hourAdvantages
worker cooperation unnecessaryworkplace uninterruptedperformance ratings unnecessaryconsistent.Disadvantages
ignores job contextmay not reflect skills and abilities of local workers
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Copyright 2006 John Wiley & Sons, Inc.Supplement 8-*MTM Table for MOVE
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Copyright 2006 John Wiley & Sons, Inc.Supplement 8-*Work SamplingDetermines the proportion of time a worker spends on activitiesPrimary uses of work sampling are to determine
ratio delaypercentage of time a worker or machine is delayed or idleanalyze jobs that have non-repetitive tasksCheaper and easier approach to work measurement
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Copyright 2006 John Wiley & Sons, Inc.Supplement 8-*Steps of Work SamplingDefine job activitiesDetermine number of observations in work sample
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Copyright 2006 John Wiley & Sons, Inc.Supplement 8-*Steps of Work Sampling (cont.)Determine length of sampling periodConduct work sampling study, record observationsPeriodically re-compute number of observations
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Copyright 2006 John Wiley & Sons, Inc.Supplement 8-*Work Sampling: Example
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Copyright 2006 John Wiley & Sons, Inc.Supplement 8-*Copyright 2006 John Wiley & Sons, Inc.All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permission Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages caused by the use of these programs or from the use of the information herein.
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