Presentation on theme: "Time Study=Work Measurement Part 1"— Presentation transcript:
1 Time Study=Work Measurement Part 1 Prof.Dr.Yasemin Claire ERENSAL
2 Work Standards Are based on the data collected through work measurement processes.They should not be set at such a level thatonly the most productive worker will beable to attain them.Nor should they be set at such a level thatnearly every employee can attain them withputting forth little effort to do so.
3 Advantages of Work Standards (1 of 2) 1. They help increase the efficiency with whichemployees perform their jobs.2. They help inform employees of their expectedproduction levels.3. They assist managers in making personneldecisions, because employees who areperforming beyond expected levels of productioncan be readily identified.
4 Advantages of Work Standards (2 of 2) 4. Because employees are aware of the proceduresfor performing their jobs, less supervision isneeded and greater control over the workprocess is possible.5. They provide the basis for incentive wagesystems.6. They help improve employee morale by makingemployees aware of what is expected of them.
5 Types of Standards Are expressed in units of Quantity output per unit of time.QuantityStandardsMeasure the accuracy andacceptability of work.QualityStandardsIdentify what is acceptable in terms of the descriptivenature of something in anoffice, such as furniture.DescriptiveStandards
6 Work MeasurementWork measurement refers to the process of estimating the amount of worker time required to produce one unit of output.Work measurement is a process of analyzing jobs for the purpose of setting time standards.The goal of work measurement is to develop labor standards that can be used for planning and controlling operations.
7 Objectives of Work Measurement (1/2) 1. To express expected output or productionlevels.2. To aid in the planning and scheduling ofwork.3. To aid in determining the number ofemployees needed to complete a project inthe allotted time.4. To aid in determining the efficiency of workmethods and procedures.
8 Objectives of Work Measurement (2/2) 5. To aid in determining the cost of officeoperations.6. To aid in determining equitable work loadsfor employees.
9 Labor StandardsA labor standard can be determined using one or more of the following approaches:subjectiveHistorical standardsSupervisor estimatesobjectiveStandard DataWork samplingTime studyPredetermined time standards
10 Production Records and Expert Opinion Time Standards and Historical Data (Subjective) Estimation of time required to do a specific time, normally performed by a supervisor – expert opinionUnfair due to variability among estimatorsLooking at a job and judging the amount of the time neededHistorical data – records of previous times used on each job– does not include what time it should have takenRelatively easy, convenient, and inexpensiveNot objective, unknown accuracyNot recommended
11 Production Records and Expert Opinion Time Standards and Historical Data (Subjective) 1. It is simple, easily understood, and inexpensive.2. It facilitates the quick development and implementation of a work measurement program without the need for specially trained individuals.
12 Disadvantages of Production Records and Expert Opinion Time Standards and Historical Data (Subjective)It may produce inaccurate standards if employees don’t prepare accurate time logs.It results in preparation of standards on the basis of “what is” rather than on the basis of “what should be.”
13 Standard DataFastest & cheapest technique – may be more accurate & consistent than any other time study technique.Compare previously set time standards to varying times on specific machines or class of machines.Communicate time standards through graphs, tables, worksheets, and formulas. Reference text (i.e. Machinery Handbook) or equipment manufacturers are a good source of standard data.
14 Work Sampling Technique (1/2) Uses a statistical base that requires random observations to determine the amount of time taken by each element of an office procedure.Statistical element is based on this law of probability: If a procedure is observed a sufficient number of times, the results will be as reliable as when the procedure is observed continuously over a period of time.
15 Work Sampling Technique (2/2) The process helps determine what percent each activity consumes in a whole work process.Observe people working & draw conclusionsThis subject will furtherly handled on the next weeks.
16 Time Study Establishes a standard for a given task Measures work content, allows for fatigue, personal and unavoidable delaysIncreases the efficiency of the equipment and personnelIf standards are accurately established, they can increase the efficiency of the equipment and personnel. Poorly established standards result in high costs, labor dissension, possibly failure of an enterprise.
17 Advantages of the Time Study Technique 1. Results in the development of accuratestandards.2. Produces more accurate results when measuringwork processes comprised of minute elementsthan either the production records technique orthe work sampling technique.3. Results in the development of standards that canbe readily used for assessing the performance ofemployees.
18 Disadvantages of Time Study Technique 1. The measurement process often requires theuse of a trained analyst.2. Office employees tend to have a negativereaction to standards determined by the use ofa stopwatch.3. The technique is not useful for measuring time-consuming elements of a work process.
19 Predetermined Standard Time Data Technique (1 of 2) Uses data typically obtained from external sources,such as purchased data.Tends to produce highly uniform results when basedon standards that are consistent from onesituation to another.Visualize needed tools, equipment, & work methods–work divided into 17 work elements (therbligs)
20 Predetermined Standard Time Data Technique (2 of 2) Steps1. The work process is broken down into itsminute elements.2. Each element is analyzed in terms of the motioninvolved.3. To determine the appropriate standard, eachmotion of the work process is compared withthe purchased predetermined standard time data.4. The standard for the entire process is found byadding the standard times for each of the motions.
22 Advantages of Predetermined Standard Time Data Technique 1. It results in accurate standards.2. Employees tend to accept results readilybecause of the specificity of the process.3. Application of process is fairly rapid.
23 Disadvantages of Predetermined Standard Time Data Technique 1. It is a costly technique.2. It is not suitable for certain types of officeoperations.
24 Performance LevelingIs a process that results in the adjustment of employee work standards, helping determine what constitutes a fair day’s work for both the employer and employee.The amount of work that can be produced by a qualified employee when working at a normal pace and effectively utilizing their time where work is not restricted by process limitations
25 Responsibilities in Work Measurement Activities
26 Analysts Responsibility Normalize timeCorrect method, and understanding by all those involved in the studyAccuracy and good judgment essentialGood human relations most important: show respectAnswer questions to allieviate fears: TS must never become vindictive: Sally FieldsSign the study
27 Supervisor's Responsibility Notify operator in advanceVerify correct tools, equipment, supplies, and method.Select a qualified, cooperative operator and answer all questions in advance of the study.Sign the study
28 Union’s Responsibility Most are opposed. They must recognize the necessity for profitability.Provide members training in TS to promote acceptance and validity.Make sure study includes a complete record of the job.May wish to be present at the time of the study.
29 Operator’s Responsibility Assist in the establishment of the most efficient method for the job.Assist in breaking down job into elements that can be usefulCooperate during the studyAvoid vigorous application of non-essential elements.Sign the studyDo not sit during the time study
30 Work Measurement Standard time: (Labor standards) The length of time a qualified worker, using appropriate tools & procedures, will take to complete a jobA labor standard is the number of worker-minutes required to complete an element, operation, or product under ordinary operating conditions.Ordinary operating conditions refers to a hypothetical average situation ….. average or typical worker, material, machinery, environment, etc.
31 Labor (Time) StandardTime required to produce a product at a work station with the following:Qualified, well-trained operatorWorking at a normal paceDoing s specific taskBefore data are gathered, all wasted motions are eliminated from the process being analyzed.Time in decimal minutes (3 decimal places)Pieces per hourHours per pieceQualified , well-trained operator – time for training varies with job and personnel – minimum two weeks on job prior to time study (predetermined time studies used with new jobs)Normal pace – walking 3 mi/hr; dealing 52 cards into 4 equal stacks in minutes; filling a 30pin pinboard in minutes using 2 handsSpecific task – detailed description of what needs to be done – includes prescribed work method; material specification; tools & equipment being used; positions of ingoing and outgoing material; safety, housekeeping, and maintenance tasksTime standard good for only one set of specific conditions – if anything changes, then need to change time standard
33 Workforce Productivity Improvement – Learning Curves A learning curve shows the reduction in time it takes to complete a task as the number of times it has been completed increases.Individuals, groups, and organizations all have learning curvesThe learning rate is the amount of improvement obtained as a task is repeated.The gain expressed by the learning rate is achieved every time the number of repetitions doubles.The learning rate is almost always a prediction. There are always errors in predictions, and errors in estimating the learning rate can have a tremendous impact on the projected time
34 Workforce Productivity Improvement – Learning Curves If an individual completed a task for the first time in 4 hours and his learning rate was expected to be 90%, we would observe the following pattern:Exhibit 16.7 Learning Curve Pattern
35 Workforce Productivity Improvement – Learning Curves A lower percentage means faster learning. 85% vs. 97% learning curves:Exhibit percent learning curveExhibit percent learning curve
36 Workforce Productivity Improvement – Learning Curves The equation for the learning curve isTn = T1nrWhereTn = time in hours to produce nth unitT1 = time in hours to produce the first unitn = number of the unit of interestr = log l/log 2 where l is the expected learning rate
37 Workforce Productivity Improvement – Learning Curves Example 16.3:A producer of machined components wants to determine the time it will take to produce the 300th unit on a new machine. The time for the first unit is 1.75 hours and the learning rate is 96%Tn = T1nrT300 = 1.75(300)log 0.96/log 2= 1.75(300)= 1.75(300)0.0589= hours
38 Training approachesINSTALL NEW METHOD:Need to train workers in new method1) 'Learn-on-the-job' approach- learn wrong method- bother other operators, lower production- anxiety2) Simple written instructions - only good for very simple jobs3) Pictorial instructions - 'pictures worth 1000 words‘4) Videotapes - dynamic rather than static5) Physical training -- real equipment or simulators, valid- doesn't interrupt production- monitor performance- simulate emergencies
39 Factors that affect human learning 1) Job complexity - long cycle length, more training, amount of uncertainty in movements, more C-type motions, simultaneous motions2) Individual capabilities- age, rate of learning declines in older age, amount of prior training, physical capabilities, active, good circulation of oxygen to brain
40 Learning CurvesAssumption is that given exposure to repetitive tasks workers are likely to learn from cumulative experience how such tasks can be performed more quickly and efficiently, e.g. the second identical house can be constructed for less than the first; learning reduces the cost of succeeding unitslearning curves relate cost to cumulative nr.s of units produced
41 Learning Curve For Mass Production Processing time decreases with worker learning (experience)Time per unit decreases by constant percentage each time output doublesUse to plan labour, budget & scheduling requirements
42 Learning Curve Definition The Learning Curve is a tool to help estimate future manufacturing costs. It is based on a relationship between cost (the dependent variable) and quantity (the independent variable)
43 History of Learning Curve • The concept of the learning curve was introduced to theaircraft industry in 1936 when T. P. Wright published anarticle in the February 1936 Journal of the AeronauticalScience.• Wright described a basic theory for obtaining costestimates based on repetitive production of airplaneassemblies.• Since then, learning curves (also known as progressfunctions) have been applied to all types of work fromsimple tasks to complex jobs like manufacturing a SpaceShuttle.
44 Theory of Learning Curve • The theory of learning is recognized that repetition of thesame operation results in less time or effort expended onthat operation.• For the Wright learning curve, the underlying hypothesis is that the direct labor man-hours necessary to complete a unit of production will decrease by a constant percentage each time the production quantity is doubled.• If the rate of improvement is 20% between doubledquantities, then the learning percent would be 80% (100-20=80).• While the learning curve emphasizes time, it can be easily extended to cost as well.
45 The Learning Curve • Learning Curve - the longer a person performs a task, the quicker it takes him Fig 18-2: Estimated cycle times based on a 20% reduction each time the quantity doubles
49 Types of LearningIndividual Learning Improvement when individuals gain a skill or efficiency by repetition of a job.Organizational LearningImprovement from the groups of individuals from repetition and changes in administration, equipment, and product design.
50 Learning Curves At the start of production runs: Workers are unfamiliar with their tasksTime it takes to produce the first few units is highAs the workers learn their tasks:Their output per day increases up to a pointThen their output levels off to a rather constant rate
51 Learning with Improvements Time per unitTimeAverageImprovements may create ascallop effect in the curve.
52 Learning CurvesMost aircraft manufacturing tasks experience an 80% learning rateLabor-hours required to assemble an aircraft is reduced by a factor of 0.8 as the production quantity doublesIf first aircraft assembled requires 100 labor-hoursSecond aircraft would require 80 labor-hoursFourth aircraft would require 64 labor-hoursEighth aircraft would require 51.2 labor-hours… and so on
53 Labor-Hours for nth Unit Learning Curves20804010060Unit Number (n)120Labor-Hours for nth UnitAircraft Assembly80% Learning Curve
54 Learning CurvesBy analyzing workers’ learning situations, we are able to estimate:The average number of labor-hours required per unit for N units in a production runThe total number of labor-hours required to produce N units in a production runThe exact number of labor-hours required to produce the nth unit of a production run
56 Learning Curve for Mass Production Job Standard timeEnd of improvementUnits producedProcessing time per unitFigure 17.7
57 Some Other Names of Learning Curves Experience CurveImprovement CurveManufacturing Progress CurveCost CurveCost Reduction Curve
58 Learning curve assumptions • The time required to complete a specified task or unit of aproduct or item will be less each time the task is performed;• The unit time will reduce at a decreasing rate;• The decrease in time will follow a certain pattern, such asnegative exponential distribution shape.• The learning curve may vary one product to another and from one organization to another. The rate of learning depends on factors such as the quality of management and the potential of the process and products
59 • The Table presents data on learning curve effects in the U.S. industrial sector . An 80% learning rate is descriptive of certainoperations in such areas as ship construction, electronic dataprocessing equipment, automatic machine production, andaircraft instruments and frame assemblies.• The learning curves are found to be quite useful in a variety ofapplications, including strategic evaluation of company andindustry performance, internal labor forecasting, establishingcosts and budgets, production planning, external purchasing,and subcontracting of items• The learning curve theory is based on a doubling of productivity.More specifically, when output or production doubles, thereduction in time per unit affects the learning curve rate. Forexample, an 80% learning rate means the second unit takes80% of the time of the first unit, the fourth unit takes 80% of thesecond unit, the eighth unit takes 80% of the fourth unit, and so
65 Curve slope can always be found using the relationship between doubled quantities
66 TheoryTheory = as number of cycles doubles, cycle time decreases by a constant %
67 TheoryResult: 20% decrease or 80% learning ratio or 80% learning curve, ormathematicallyy = kxn• However, easier to plot and calculate if on log-log paperlog10 y = log10k + n×log10 xwhere: y = cycle timex = number of cycles or units producedn = exponential representing the slopek = value of first cycle timeor, rearranging and solving for n:n = log10(learning percent)/log102For 80% learning: n = log10(0.80)/log102= /0.301 =
68 Theory Or from the slope: n = (log10 y1 - log10 y2)/(log10 x1 - log10 x2)n = (log log )/(log log10 16) = ( )/( ) = -.322• solve for k, by substituting (1,12) into the main equation yielding k=12,therefore the final equation for the learning curve:y = 12 x -.322
69 Theory• a) MTM-2 analysis shows a standard time of 2 min. How many cycles does it take to reach it?• 2 = 12 x -.322• Then take logs of both sides and solve for x:log10 (2/12) = log10 xlog10 x = /-.322 = 2.417x = antilog = = 262 (round up!!)
70 Learning Curves Three approaches to learning-curve problems are: Arithmetic analysisLogarithmic analysisLearning curve tables
71 Learning Curves Arithmetic Analysis The simplest approach to learning-curve problemsIf we wish to find the labor-hours required to produce n units, and n just happens to be a number that is one of the doubled values, then this approach works
72 Example: EZ Machine Shop (A) Learning Curve - Arithmetic AnalysisEZ Machine Shop has a contract to manufacture 100 turbines. The first 20 turbines have been completed. The labor-hours required for a portion of the completed turbines are listed below. Use this data to estimate the shop’s learning rate in manufacturing the turbines.Unit No. Labor-Hours Unit No. Labor-Hours
73 Example: EZ Machine Shop (A) Learning Curve - Arithmetic AnalysisCompute the learning rate for each of the “doubles”.Units 1 and 2 118/140 =Units 2 and 4 102/118 =Units 5 and 10 81/ =Units 10 and 20 68/ =( )/4 = .8499The approximate learning rate is 85%.
74 Learning Curves Learning-Curve Tables A table of learning curve coefficients allows us to compute:The labor-hours for the nth unit in a production runThe total labor-hours for the entire production run, where the nth unit is the last unit in the run
75 Example: EZ Machine Shop (B) Learning-Curve TablesThe manager of EZ Machine Shop wants a good estimate of the total labor-hours required to manufacture the entire 100 turbines. Also, he is curious about how many labor-hours will be needed for the last (100th) unit. Use the observed 85% learning rate and 140 labor-hours required for the first turbine to compute your estimates.
77 Example: EZ Machine Shop (B) Learning-Curve TablesTotal Labor-Hours Required for 100 Units= (Hours for 1st unit)(Table total time: 85%, 100th unit)Look at Table, locate the line for the 100th unit and read across to the Total Time column under the 85% learning rate. The value is= 140(43.75) = 6,125 labor-hours
78 Example: EZ Machine Shop (B) Learning-Curve TablesLabor Hours Required for the 100th Unit= (Hours for 1st unit)(Table unit time: 85%, 100th unit)In Table, locate the line for the 100th unit and read across to the Unit Time column under the 85% learning rate. The value is .340.= 140(.340) = labor-hours(100th unit will require 34% of the time 1st unit required)
79 Learning Curves Logarithmic Analysis The following relationship allows us to compute Tn, the labor-hours required to produce the nth unit:Tn = T1(nb) and b = log r/log 2where: T1 = labor-hours to produce the first unitb = slope of the learning curveb = ln r / ln 2, where r is the percentage rate of improvementr = learning rate percentage
80 Example: EZ Machine Shop (C) Logarithmic AnalysisCompute, using logarithmic analysis, the labor-hours required for the 50th turbine (assuming an 85% learning rate and 140 labor-hours required for the 1st unit).b = log (.85)/log (2) =T50 = 140( )= or(Our result agrees with the value in Table 18.12)
81 Major Issues in Application Selection of SlopeRate of ProductionBreaks in ProductionHow long does learning go on?
83 More On Learning Curves Not effective for mass production jobsProduct modifications negate effectsImprovement can derive from sources besides learningIndustry-derived learning curve rates may be inappropriate
84 Some Factors Affecting Improvement Rate Previous experienceDesign complexityLabor grades/mixTraining/supervisionParts availabilityWorkmanship standardsTooling availabilityDegree of automationChanges in configurationSupport and servicesPersonnel turnoverRate of productionTotal quantityLapses in productionSchedule fluctuationParts qualityTolerancesOutside influences (e.g., the customer)
85 Some Problems in Curve Application Learning Curves are a technique to help predict the future; they are inherently inexactTechnique is subjective and judgmentalFrequent misuseOccasional abuseLack of complete understanding by many practitioners
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