WORK DESIGN AND MEASUREMENT

1
WORK DESIGN AND MEASUREMENT

• Specialists versus Generalists
• Methods Analysis Motion Study
• Work Measurement
• Learning Curves

2
SPECIALISTS VS. GENERALISTS

• Ideal employee a low-wage highly skilled
  generalist
• Typical choice
• High-wage skilled generalist
• Low-wage unskilled person who can be quickly
  trained as a specialist
• Historically, as production volume increases
  generalists are replaced with specialists

3
SPECIALISTS VS. GENERALISTS

• Unskilled specialist labor comes with problems
• Motivational issues (absenteeism, poor quality,
  hostility)
• Disconnect between designers and doers frustrates
  process improvement
• Possible solutions
• Job enlargement each worker covers a larger
  portion of the production process
• Job rotation workers switches jobs every X
  hours
• Job enrichment workers are given more
  responsibility and control

4
SPECIALISTS VS. GENERALISTS

• Self-Directed Work Teams have elements of all
  three potential solutions
• Workers for a certain section of the production
  process are formed into a team
• The team may elect its own leader
• The team is given quality and volume requirements
• The team is responsible for deciding how best to
  meet those requirements (with the help of
  professional staff)
• The team is given training in quality and process
  improvement
• Team members may be compensated based partly on
  team performance and partly on individual
  knowledge
• Additional training costs are offset by
  efficiency, flexibility, and quality

5
METHODS ANALYSIS MOTION STUDY

• Tools used by managers, industrial engineers, and
  team members to analyze and improve a job or
  process
• Methods analysis big picture
• Most common tool process flow diagram/chart
• Analysis of operations sequence for redundancy,
  efficiency
• Motion study little picture
• Application of Motion Study Principles to a
  single operation
• Break movement down into Therbligs

6
METHODS ANALYSIS EXAMPLE

• Example impact of new Enterprise System on
  transcript retrieval

7
MOTION STUDY

• Detailed critique of job using Motion Study
  Principles
• Motions made by the hands should be done
  symmetrically
• All materials and tools should be located within
  the normal working area?
• Parts should be held in position by fixtures
• Further detailed analysis of therbligs, or
  elemental motions
• Search, select, reach, grasp, hold
• Aim is to eliminate elements and simplify job

8
WORK MEASUREMENT

• How long does (or should) a job take?
• Needed input for capacity analysis, facility
  layout/relayout
• Existing Jobs
• Time study
• New jobs
• Time standards

9
TIME STUDY

• Worker is timed doing the task and the resulting
  time is adjusted for worker performance, fatigue,
  and other factors
• OT Observed time
• Average time to do job by worker being observed
• PR Performance rating
• Indicates estimated performance of worker being
  observed relative to an average worker

10
TIME STUDY

• NT Normal time
• Average time to do job by an average worker
• NT (OT)(PR)
• AF Allowance factor
• Gives worker extra time for fatigue, restroom
  breaks, getting materials, etc.
• ST Standard time
• Average time for an average worker including time
  for fatigue, restroom breaks, etc.
• ST (NT)(AF)

11
TIME STUDY

• Example An experienced worker is observed
  assembling a circuit board 30 times.
• The average observed time is 3.5 minutes per
  board
• The worker is assumed to be about 20 faster than
  the average worker
• The firm has a policy of allocating an extra 10
  of time for fatigue, restroom breaks, etc.
• NT (3.5)(1 0.2) 4.2
• ST (4.2)(1 0.10) 4.62 minutes

12
TIME STUDY

• How many observations?
• n number of required observations
• a desired percentage accuracy
• z z score for percentage confidence (z 2 ?
  95.5 confidence)
• OT mean observed time so far
• SOT standard deviation of observed times
• To be 95.5 confident of being within a of the
  true mean time, set n such that

13
TIME STUDY

• Example suppose we want to be 95.5 sure that
  our new standard time for the circuit board
  assembly operation is no more than 2 off the
  true mean.
• Our OT was 3.5
• We find the standard deviation of the 30
  observations to be 0.3.

14
TIME STANDARDS

• Laboratory tests have determined standard times
  for all therbligs under all possible conditions
• Methods time measurement (MTM) tables time all
  basic movements in TMUs
• Time measurement units (1 TMU0.0006 minutes)
• Avoids Hawthorne effect
• E.g. how much time to move an object to an
  indefinite location?
• Weight up to 2.5 pounds
• Distance between ¾ and 1 inches
• Time 2.9 TMUs, or 2.9x0.0006 0.00174 minutes

15
WORK SAMPLING

• Used to estimate the fraction of time a worker
  performs a non-routine task
• time a professor spends in meetings
• Every x minutes, professor records activity
• If 20 out of 100 times he was in meetings, the
  desired ratio is 20
• The time interval x should be random

16
WORK SAMPLING

• How many observations?
• n number of required observations
• e desired maximum error
• z z score for percentage confidence (z 2 ?
  95.5 confidence)
• p mean estimate of fraction so far
• To be 95.5 confident of being within e of the
  true mean time, set n such that

17
WORK SAMPLING

• Example suppose we want to be 95.5 sure that
  our new estimate of the fraction of the
  professors time spent in meetings is no more
  than 5 off the true mean.
• Our initial estimate of p was 0.2

18
LEARNING CURVE

• The more you do something, the faster you can do
  it
• A formal model can be used for estimating
  standard times far into the future
• Basic principle as cumulative production
  doubles, the time required per unit decreases to
  a fraction of the previous required time
• That fraction is the learning rate
• Notation
• Tn -- time required for nth unit
• LR -- learning rate

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19
LEARNING CURVE

• Suppose that we have a new assembly
• The first unit takes 10 hours to assemble
• The learning rate of a similar product was 90
• How long will the 25th unit take?

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