SU3 - Chapter 1 Service Processes: © 2015 SIM University. All Rights Reserved
SU3 - Chapter 1 Service Processes: © 2015 SIM University. All Rights Reserved
SU3 - Chapter 1 Service Processes: © 2015 SIM University. All Rights Reserved
Service Processes
The
customer
Support
Employees
systems
Service Package
The physical
The material
resources Psychological
purchased by Benefits that
that must be Data benefits the
the buyer or are
in place provided by customer
the items observable by
before a the customer may sense
provided to the senses.
service can only vaguely
the customer.
be offered
1. Arrival variability
• e.g., Customers arriving at times when there are not enough service providers
2. Request variability
• e.g., Travelers requesting a room with a view
3. Capability variability
• e.g., Patients not being unable to explain symptoms to doctor
4. Effort variability
• e.g., Shoppers not returning shopping carts to the designated area in a
supermarket parking lot
5. Subjective preference variability
• e.g., Customers interpreting service action differently
Managing Customer-Introduced Variability
• In general,
Performance Features
Reliability/Durability Serviceability
Quality Costs
• The name, “Six Sigma,” refers to the goal of no more than four defects per
million opportunities (DPMO)
Number of defects
DPMO = x1,000,000
Number of opportunities for error per unit x number of units
• By this metric, a process that is said to meet six sigma standard produces
maximum 3.4 DPMOs.
Activity 3.2
What is DPMO?
Process control chart - used to assure that processes are in statistical control
Variation in Process - Statistical Quality Control (SQC)
Assignable variation
• Variation that is caused by
factors that can be identified
and managed
Common variation
• Variation that is inherent in the
process itself
Measuring Variation
Process Capability
Definition:
The ability of a process to consistently produce a good or
deliver a service with a low probability of generating a
defect.
• Specification limits – range of variation that is considered
acceptable by the designer or customer
• e.g. 10.00 ± 0.02 will give you upper limit of 10.02 and lower
limit of 9.98, (9.98, 10.02)
• Process limits – range of variation that a process is able to
maintain with a high degree of certainty
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Process Capability
Process Capability
Shows how well the parts being produced fit into the range
specified by the design specifications
• Used when an item (or service) is either good or bad (a yes-no decision)
(1)
(5)
Textbook Example 13.2: using p-Chart
Based on the plotted data point, what comments can you make?
𝑛 𝑚
𝑗=1 𝑋𝑖𝑗 𝑖=1 𝑋𝑖
• 𝑋𝑖 = , 𝑋=
𝑛 𝑚
• 𝑈𝐶𝐿𝑋 = 𝑋 + 𝑧 𝑆𝑋 , 𝐿𝐶𝐿𝑋 = 𝒎𝒂𝒙 𝑋 − 𝑧 𝑆𝑋 , 0
• 𝑋𝑖 is the mean of the ith sample,
• 𝑋 is the average mean of the samples
• 𝑆𝑋 = 𝑠/ 𝑛 = standard deviation of sample mean,
• s = standard deviation of the process distribution
• n = sample size
• M = number of samples
• z is the number of standard deviations for a specific
confidence level (99.7% CI, z = 3)
Size of samples
Preferable to keep small (usually 4 or 5 units)
Number of samples
Once chart set up, each sample compared to chart
Use about 25 samples to set up chart
Frequency of samples
Trade-off between cost of sampling and benefit of adjusting
the system
Control limits
Generally use z = 3
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