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Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 1
Chapter 12.
Quality Control
UCL
LCL
Sample number
1 3 4 5 6 7 8 9
2 10 11 12
CL
x
+1σ
-1σ
-2σ
-3σ
+2σ
+3σ R
A
x
A
Zone 2


R
A
x
B
Zone 2
2
1


R
A
x
C
Zone 2
3
1


R
A
x
B
Zone 2
2
1


R
A
x
C
Zone 2
3
1


R
A
x
A
Zone 2


Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 2
Outline
 Quality in Healthcare
 Quality Experts
 Quality Certification
 TQM & CQI
 Six-Sigma
 Monitoring Quality through Control Charts
– Control Charts for Attributes
– Control Charts for Variables
 Process improvement
 Methods for Generating New Ideas
 Tools for Investigation
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 3
A Broad Definition. . .
 Quality refers to the ability of a product or
service to consistently meet or exceed customer
expectations
 quality in healthcare is evaluated from differing
perspectives of providers, recipients and third-
party payers.
 Most clinicians accept the Institute of Medicine
(1990) definition: “Quality is the extent to which
health services for individuals and populations
increase the likelihood of desired health
outcomes and are consistent with current
professional knowledge.”
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 4
What is quality?
You are a world renowned surgeon that
has just completed a radical new
surgical technique. There were few
complications, largely due to the
excellence of the hospital’s staff and
technological capabilities.
QUALITY?
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 5
What is Quality?
You are a patient who has just undergone
radical new surgery. Although the surgery
went without technical difficulties, your were
upset at the doctor’s uncaring attitude.
Furthermore, the nursing staff often failed to
respond to your calls, and twice you were
served meat despite the fact that you are a
vegetarian. Also, there was a used bedpan
that sat next to your bed for three days.
QUALITY?
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 6
A question of perspective
 Quality of care depends upon who is
making the assessment
– Clinician-- technical components, adequate
skills, resources, conditions
– Patients-- outcomes, interpersonal
processes, amenities, overall satisfaction
– Health Facility Managers- appropriate and
effective utilization
– Community-- availability, access,
reputations, general health status of
community
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 7
Quality Measurement
 Clinicians-- cure rates, mortality, morbidity
 Patients-- patient satisfaction surveys
 Health facility managers-- cure rates,
mortality, morbidity, intermediate process
measures (patient falls, infection rates,
medication errors, appropriate staffing, etc.)
 Community-- area service distribution,
insurance coverage, incidence and prevalence
rates, etc.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 8
Figure 12.1 Quality Measurement
Structure Process Outcome
Inputs
Conversion Process
(Throughput)
Outputs
Patient,
provider labor
equipment
supplies, etc.
Various hospital
and medical services
transform poor health
to wellness for patients
(diagnosis, procedures,
treatments)
Treated
Patient
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 9
Quality Measurement
Another way to look at the maintenance of quality is how
mistakes are to be avoided – design mistake-proof processes
across the whole spectrum of the care, to reduce undesired
outcomes.
Variance in diagnostic and therapeutic interventions and the
associated errors hamper the delivery of safe, effective
patient care and add to poor outcomes.
To minimize the variation and the errors – sometimes
euphemistically called “quality gaps” – and work toward
completely eliminating them are major goals for healthcare
systems.
Quality Gaps
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 10
Quality Measurement
Chassin (1998) classifies the underlying causes of “quality
gaps” into three categories:
1) Over-utilization. When the potential benefit of a therapy
is less than its risk, overuse of health services affects the
quality of care. Pressures for overuse of services may come
from either providers or patients.
2) Under-utilization. A patient’s lack of insurance or
insurance that has high co-payments and deductibles can
cause under-utilization of necessary health care.
3) Miss-utilization. Avoidable complications, negligent care,
mistakes, and mishaps create miss- utilization of services.
Healthcare providers who generate such conditions harm the
quality of patient care and produce poor outcomes; they also
waste the organization’s resources and increase lengths of
stay.
Quality Gaps
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 11
Quality Measurement
Healthcare providers do have an arsenal of methods to deal
effectively with the problems affecting quality of care.
They include the programs called quality control (QC), total
quality management (TQM), continuous quality improvement
(CQI), reengineering, and Six-Sigma.
All these programs include data gathering, analysis and
statistical monitoring to identify the problem and its cause.
Nevertheless, the crux of the solution to quality problems
lies in changing human behavior, changing minds to perform
care in new ways.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 12
Quality Experts
 Deming-- poor quality caused by the system, not
employees; management’s responsibility to correct
system;” use 14 points to reduce variation caused by
special causes (correctable) and not common (random)
causes of variation.
 Juran-- 80% of defects are controllable; three
elements: quality planning, quality control, and
continual quality improvement
 Crosby-- zero defects; quality is free
 Isikawa-- cause and effect diagrams, quality circles
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 13
 Organizations can earn awards or achieve
certification/accreditation by international organizations or
by their own trade organizations; for instance, hospitals
are evaluated periodically by the Joint Commission on
Accreditation of Healthcare Organizations (JCAHO).
 For the medical group practices, the Medical Group
Management Association (MGMA) is the principal voice.
MGMA leads the profession and assists members through
information, education, networking and advocacy” (MGMA,
2004).
 Quality is always a major concern in those advocacy and
accreditation bodies.
Quality Certification
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 14
Quality Certification
 ISO 9000
 Set of international standards on quality management
and Quality assurance, critical to international
Business
 ISO 9000 series standards, briefly, require firms to
document their quality-control systems at every step
(incoming raw materials, product design, in-process
monitoring and so forth) so that they’ll be able to
identify those areas that are causing quality problems
and correct them.
 ISO 9000 requires companies to document everything
they do that affects the quality of goods and services.
– Hierarchical approach to documentation of the
Quality Management System
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 15
Total Quality Management
 A philosophy that involves everyone in an
organization in the quest for quality, with
customer satisfaction as the driving force
 TQM involves:
– finding what customers want
– designing services to meet customer needs
– designing mistake proof delivery process
“pakayoke”
– monitoring results and continuous
improvement
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 16
TQM, cont.
 TQM requires:
– continual improvement
– competitive benchmarking
– employee empowerment
– team approaches
– knowledge of tools
 Quality at the source-- each worker responsible for
his/her own work
 Quality function deployment-- involve customers in
service design
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 17
Controlling Quality
 Quality control focuses on the conversion of
inputs into outputs, i.e., the processes
 Goal is to reduce the need for inspection of
control efforts
 Quality assurance efforts occurring during
production of services are referred to as
statistical process control
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 18
Plan
Do
Act
Check
Figure 12.2 The Deming Wheel/Shewhart Cycle
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 19
Continuous Quality Improvement
 A philosophy seeking to make never-ending
improvements to the process of converting inputs into
outputs
 Kaizen-- Japanese term referring to CI
 Environment must be conducive to CI
– appropriate vision statement, strategies, tactics
– management style encouraging trust, openness
– adherence to stated philosophy
– reward/incentive systems
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 20
The CQI is a detailed version of a PDSA cycle that
comprises:
1) selecting a process that needs an improvement
2) studying and documenting the current process seeking
ways to improve it
3) designing an improved process
4) implementing the new process
5) monitoring and evaluation
6) documenting the process if it worked successfully and
publicizing it through the healthcare organization
7) if it did not achieve its goals, re-starting from step 1.
Continuous Quality Improvement
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 21
Six-Sigma
•Six- Sigma is one of the latest quality improvement
concepts to have emerged during the 1990’s. Its
name comes from the measure of variation from the
normal distribution (six standard deviations).
•Adopting a six-sigma strategy as a quality goal
sets tolerance levels for errors (defectives) to
levels that occur only 3.4 times per million
observations.
•The defect rates in healthcare can be defined in
such distinct areas as public health, inpatient care,
ambulatory care, and so on.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 22
Six-Sigma
Healthcare organizations have reduced the deaths
caused by anesthesia from 25-50 per million cases
to 5 per million cases since the 1980s through
improved monitoring techniques, adaptation of
practice guidelines, and other systematic
approaches to reduce errors.
This is one area that comes very close to six sigma
standards (Chassin, 1998).
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 23
Six-Sigma
Deployment of six-sigma to improve the quality of
healthcare and delivery performance can be
considered in the following areas:
a) Clinical excellence
b) Service delivery
c) Service costs, and
d) Patient satisfaction.
The deployment can use either of these
methodological sequences:
DMAIC: define, measure, analyze, improve, and control
DMADV: define, measure, analyze, design, and verify.
DMAIC is generally used to improve existing systems that have
fallen the below six-sigma levels,
DMADV is used to design and develop new processes or products
at six-sigma levels (Stahl, Shultz, and Pexton, 2003).
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 24
Six-Sigma
The essence of six-sigma methodologies is both improvement
of the knowledge and capability of employees, and also
changes behavior through training. Thus six-sigma employs a
classification system that identifies education and training for
employees, project managers and executives.
Emulating karate honors, certification is granted at Green Belt
(GB), Black Belt (BB) and Master Black Belts (MBB) levels.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 25
Six-Sigma
Green Belts (GBs) are the employees who have taken the
training courses on implementing the projects.
Black Belts (BBs) are the project leaders, whose training may
be more intensive; they may complete several projects a year
depending upon their size and scope.
Master Black Belts (MBBs) are generally assigned to an area
that needs improvement (for example, human resources), to
ensure that objectives are set, targets are identified, plans are
made, and resources are secured to implement the projects in
their assigned area.
MBBs may oversee many six-sigma projects at a time, working
with various BBs.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 26
Six-Sigma
Six-sigma projects require BBs and MBBs to have expertise in
basic statistical tools such as Pareto Diagrams, descriptive and
higher level statistics including regression, and statistical
modeling techniques as well as control processes.
In addition to statistical concepts, they are expected
understand project management, finance, leadership,
measurement through socio-metric (survey) analysis,
reliability and validity.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 27
Six-Sigma
Examples of successful six-sigma deployments in healthcare
include:
•reduction of emergency room diversions
•fewer errors in operating rooms’ cart materials
•reduced bloodstream infections in an ICU, and
•improved radiology turnaround time (Stahl, Shultz, and
Pexton, 2003).
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 28
Quality Measurement and Control Techniques
Process Variability
In the delivery of health care, there are many occasions when an error
can happen in the tasks performed by various clinical staff.
Often the same task may not even be performed the same way for all
patients, though minor alterations within defined limits can be
acceptable.
When provider performance falls beyond acceptable limits, the errors
that occur require investigation and correction.
In order to detect noteworthy variations in process, or tendencies that
may cause unacceptable levels of errors, healthcare managers must
monitor the processes for quality, using various charts.
The intent of the monitoring is to distinguish between random and
non-random variation.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 29
Quality Measurement and Control Techniques
Process Variability
The common variations in process variability that are
caused by natural incidences are in general not repetitive,
but various minor factors due to chance and are called
random variation.
If the cause of variation is systematic, not natural, and the
source of the variation is identifiable, the process variation
is called non-random variation.
In healthcare, non-random variation may occur by not
following procedures, using defective materials, fatigue,
carelessness, or not having appropriate training or
orientation to the work situation, among many reasons.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 30
Quality Measurement and Control Techniques
Process Variability
Process variation is the range of natural variability
in a process for which healthcare managers use
control charts to monitor the measurements. If the
natural variability or the presence of random
variation exceeds tolerances set by control charts,
then the process is not meeting the design
specifications.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 31
Set design specifications
for process capability
Process
Variability
UCL
LCL
Process variability meets
and exceeds specifications
Process variability
does not meet
design specifications
Figure 12.3 Process Capability
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 32
Figure 12.4 Control Limits, Random and Nonrandom Sample Observations
Upper
Control
Limit
(UCL)
Lower
Control
Limit
(LCL)
Process
Mean
Sample number
1 3 4 5 6 7 8 9
2 10 11 12
Non-random
α/2
α/2
95.5%
+2σ
-2σ
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 33
Control Charts for Attributes
When process characteristics can be counted,
attribute-based control charts are the appropriate way
to display the monitoring process.
If the number of occurrences per unit of measure can
be counted, or there can be a count of the number of
bad occurrences but not of non-occurrences, then a
c-chart is the appropriate tool to display monitoring.
Counting also can occur for a process with only two
outcomes, good or bad (defective); in such cases
p-chart is the appropriate control chart.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 34
Control Charts for Attributes: c-Chart
c
z
c
UCL 

c
z
c
LCL 

Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 35
Control Charts for Attributes: c-Chart
Example 12.1
The number of infections from the Intensive Care Unit (ICU) at the ABC
Medical Center over a period of 24 months is obtained. These numbers
are the counts of stool assay positive for toxin, segregated by month.
The patient population and other external factors such as change in
provider have been stable.
Months Infections in ICU
Year 1 Year 2
January 3 4
February 4 3
March 3 6
April 4 3
May 3 4
June 4 3
July 5 5
August 3 6
September 4 3
October 3 3
November 7 6
December 4 3
Total 47 49
The nurse manager who serves on the quality team wants to discover whether the
infections are in control within 95.5% confidence limits.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 36
Control Charts for Attributes: c-Chart
Solution
If we consider each month as a sample of bad quality outcomes, for 24
samples we have a total of 96 quality defects (infections), and the
average would be:
c = 96/24 = 4.0.
Since the z-value for 95.5% confidence level is equal to 2, using
formulas we obtain:
.
8
2
*
2
4
4
2
4 





 c
z
c
UCL
.
0
2
*
2
4
4
2
4 





 c
z
c
LCL
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 37
Figure 12.5 ABC Medical Center Infection Control Monitoring
UCL=8
LCL=0
Sample number
1 3 4 5 6 7 8 9
2 10 11 12 13 14 15 16 17 18 19 20 22
21 23 24
Infections
per
month
4

c
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 38
Control Charts for Attributes: p-Chart
The proportion of defects in a process can be monitored using a
p-chart that has binomial distribution as its theoretical base. The
center of the p-chart represents the average for defects and LCL
and UCL are calculated as:
n
p
p
z
p )
1
(
UCL 


n
p
p
z
p )
1
(
LCL 


Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 39
Example 12.2
The indicator Family Satisfaction, which is part of the National Hospice and Palliative Care
Organization’s survey, reflects the percentage of respondents who would not recommend the
hospice services to others. The following data are from Holistic Care Corporation’s completed
surveys from 200 families each month during a year, showing the number of respondents each
month who expressed dissatisfaction with the organization’s services.
Control Charts for Attributes: p-Chart
Months Dissatisfied
Patient
Families
Percent
Dissatisfied
January 12 0.060
February 14 0.070
March 16 0.080
April 14 0.070
May 25 0.125
June 14 0.070
July 15 0.075
August 16 0.080
September 14 0.070
October 14 0.070
November 24 0.120
December 14 0.070
Total 192 0.080
The manager in charge of quality wishes to construct a control chart for this data within 95.5%
confidence intervals.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 40
Solution:
First, we need to estimate the proportion mean,
Total number of quality infractions 192 192
= -------------------------------------------- = ----------- = ------- = .08
Total number of observations 12 (200) 2400
Since the z value for the 95.5% confidence level is equal to 2.0,
using formulas we obtain:
Control Charts for Attributes: p-Chart
p
.
118
.
0
2
08
. 200
)
08
.
1
(
08
.




UCL
.
042
.
0
2
08
. 200
)
08
.
1
(
08
.




LCL
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 41
Figure 12.6 Holistic Care Corporation’s Quality Monitoring
UCL=.118
LCL=0.042
Sample number
1 3 4 5 6 7 8 9
2 10 11 12
Proportion
of
Families
Dissatisfied
08
.

p
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 42
Figure 12.7 Use of Mean and Range Charts
UCL
LCL
Process
Mean
Range indicator
Mean indicator
UCL
LCL
Stable mean, increasing range process
Increasing mean, stable range process
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 43
Mean Charts - Standard Deviation Approach.
Control Charts for Variables

z
x
UCL 

In general the population standard is unknown, and so the average of sample means )
(x
and the standard deviation of sample distribution σ
x
are used to construct the confidence limits as:
x

z
x
LCL 
 x
where σ x n
s/

.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 44
Example 12.3
With a time-motion study, the IV startup process has been examined in a
medical center nursing unit for five weekdays to determine whether in the
future, additional training of nurses is required. Each day 9 new patients’
IV startups were observed and the measurements recorded in minutes, as
shown below. Construct 99.7% (z = 3) confidence limits for IV startup
times.
Control Charts for Variables: Mean Chart, σ Method
Observation Day-1 Day-2 Day-3 Day-4 Day-5
1 5.1 4.9 5.5 6.1 6.0
2 5.4 5.7 5.6 5.8 5.2
3 5.5 6.3 5.3 5.9 6.3
4 5.8 7.5 4.9 6.0 5.0
5 5.6 5.8 5.2 6.2 5.5
6 5.8 5.9 5.4 5.7 5.1
7 5.3 5.5 6.4 4.8 5.9
8 4.9 5.8 7.5 6.3 5.3
9 6.2 5.5 5.8 5.9 4.8
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 45
Solution
Observation means for each day (sample) are calculated and are
shown in the last rows of the following table.
Control Charts for Variables: Mean Chart, σ Method
x
Sample Day-1 Day-2 Day-3 Day-4 Day-5
5.51 5.88 5.73 5.86 5.46
s 0.6
x = (5.51+5.88+5.73+5.86+5.46) ÷ 5 = 5.69.
with z = 3, n = 9 observations per sample (day), and s = 0.6, we obtain:
.
29
.
6
)
2
.
0
(
3
69
.
5
)
9
/
6
.
0
(
3
69
.
5 




UCL
.
09
.
5
)
2
.
0
(
3
69
.
5
)
9
/
6
.
0
(
3
69
.
5 




LCL
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 46
Mean Charts - Range Approach.
Control Charts for Variables
Another way to construct a mean chart is to use the average of
sample distribution ranges,. This approach requires a factor to
calculate the dispersion of the control limits.
.
R
A
x
UCL 2


R
A
x
UCL 2


Where A2 is a factor from Table 12.1
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 47
Table 12.1 Factors for Determining Control Limits for Mean and Range Charts
(for 3-sigma or 99.7% confidence level)
Sample Size
n
Factor for Mean
Chart, A2
Factors for Range Chart
LCL, D3 UCL, D4
2 1.88 0 3.27
3 1.02 0 2.57
4 0.73 0 2.28
5 0.58 0 2.11
6 0.48 0 2.00
7 0.42 0.08 1.92
8 0.37 0.14 1.86
9 0.34 0.18 1.82
10 0.31 0.22 1.78
Source: p. 143, Operations Management by Rusell & Taylor, 1995.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 48
Example 12.4
During 5 weekdays, each day the number minutes spent for each
of 10 patient registration operations were observed in a time
study as follows:
Control Charts for Variables: Mean Chart, Range Method
Observation Day-1 Day-2 Day-3 Day-4 Day-5
1 10.2 10.3 8.9 9.5 10.5
2 9.7 10.9 10.5 9.7 10.2
3 10.3 11.1 8.9 10.5 10.3
4 8.9 8.9 10.5 9.8 10.9
5 10.5 10.5 9.8 8.9 11.1
6 9.8 9.7 10.2 10.5 9.8
7 10.0 8.9 8.9 10.4 9.5
8 11.3 10.5 10.5 8.9 9.7
9 10.7 9.8 9.7 10.5 10.5
10 9.8 11.3 10.5 9.8 8.8
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 49
Solution
The overall mean for each sample and range is required to apply
the formulas, using the range approach. Here each day is
considered as a sample. The range is calculated by taking the
difference between the maximum and minimum of each sample
(day). The, mean for each day also is calculated and shown as
follows:
Control Charts for Variables: Mean Chart, Range Method
x
Sample Day-1 Day-2 Day-3 Day-4 Day-5
Maximum 11.3 11.3 10.5 10.5 11.1
Minimum 8.9 8.9 8.9 8.9 8.8
Range 2.4 2.4 1.6 1.6 2.3
10.12 10.19 9.84 9.85 10.13
x = (10.12+10.19+9.84+9.85+10.13) ÷ 5 = 10.03.
R = (2.4+2.4+1.6+1.6+2.3) ÷ 5 = 2.06.
UCL = 10.03 + 0.31 (2.06) = 10.67.
LCL = 10.03 – 0.31 (2.06) = 9.39.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 50
Range Charts
Control Charts for Variables
Process dispersion is best monitored by range charts. The
control limits for range charts are constructed using factors. To
calculate LCL, factor score D3 is obtained from a factor chart
(Table 12.1) based on the number of observations in the sample
distributions. Similarly, to calculate UCL, factor score D4 is
required. Control limits for range charts using these factor
scores are then constructed as follows:
.
R
D
UCL 4

R
D
LCL 3

Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 51
Example 12.5
Use the information provided in example 12.4 to construct a
range chart.
Solution
For n = 10, D3 and D4 from Table 12.1 are 0.22 and 1.78,
respectively. Using formulas we obtain:
Control Charts for Variables: Range Chart
UCL = 1.78 (2.06) = 3.67.
LCL = .22 (2.06) = 0.45.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 52
Investigation of Control Chart Patterns
A pattern in a control chart described by a sequence of
observations that have similar characteristics is called a “run.”
A simple classification of sample observations with respect to
the center line that identify consecutive patterns is called an
Above/Below run, or A/B run.
Up (U) and down (D) runs is another way to classify and
observe patterns. To classify sample observations as U or D, the
first observation is used as a reference point
.
Run-Based Pattern Tests.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 53
Figure 12.8 Identification of Runs
UCL
LCL
Sample number
1 3 4 5 6 7 8 9
2 10 11 12
A B B B
B B
A A A A A A
D D D
D
D
D
U
U D
U U
*
Observed runs
6
5
1 2 4
3 6
5
1 2 3 5
4
CL
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 54
Investigation of Control Chart Patterns
Control chart patterns identified by runs require statistical
testing of whether the runs are within expectations and hence
the patterns are random, or beyond expectations and hence
non-randomness is present. It has been shown that runs are
distributed approximately normally (Stevenson, 2002, p.436)
and using the z-test the significance of too few or too many
observed runs can be determined as follows:
.
Run-Based Pattern Tests.
runs
of
deviation
dard
S
runs
Expected
runs
Observed
z
tan


A z-value within ±2, which provides 95.5% confidence level,
would show that the runs are random; however, beyond
these values ≤ ±2 ≥, a non-random presence would be
shown.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 55
Investigation of Control Chart Patterns
It is necessary to calculate the expected runs and their standard
deviations. The formulas for expected A/B or U/D runs and
their standard deviations are as follows:
.
Run-Based Pattern Tests.
1
2
)
( / 

N
run
E B
A
4
1
)
( /


N
run B
A

3
1
2
)
( /


N
run
E D
U
90
29
16
)
( /


N
run D
U

Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 56
Example 12.6
Determine the presence/absence of non-randomness for the
example presented in Figure 12.8, with 95.5% confidence limits.
Solution
The example has twelve observations, so N=12. Using the
formulas we get:
Investigation of Control Chart Patterns
0
.
7
1
2
12
)
( / 


B
A
run
E 66
.
1
75
.
2
4
11
4
1
12
)
( / 




B
A
run

67
.
7
3
1
)
12
*
2
(
)
( / 


D
U
run
E 35
.
1
81
.
1
90
163
90
29
)
12
*
16
(
)
( / 




D
U
run

60
.
0
66
.
1
7
6
/ 



B
A
z
98
.
1
35
.
1
67
.
7
5
/ 



D
U
z conclude that U/D runs exhibit randomness.
conclude that the A/B runs exhibit randomness.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 57
Investigation of Control Chart Patterns
An alternative method that is often used by quality control
software packages is called the “zone test.” The essence of the
zone test rests on deviation from the center line by 1-sigma, 2-
sigma, or 3-sigma limits. Zone C, zone B and Zone A are
identified by these limits, respectively.
To create the zones, the formulas for constructing mean chart
with range approach formulas are used. Those formulas,
presented earlier, use A2 from Table 12.1, and the values for this
table were calculated for 3-sigma levels (or 99.7% confidence
level). Thus, in constructing the zones, one must reduce the A2
factor proportionately, according to the sigma level. Since A2 is
designated for 3-sigma, for 2-sigma 2/3 of A2, and for 1-sigma
1/3 of A2 would be appropriate. The zone formulas can be
written as:
.
Zone Tests.
R
A
x
A
Zone 2


R
A
x
B
Zone 2
2
1


R
A
x
C
Zone 2
3
1


Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 58
Figure 12.9 Zone test
UCL
LCL
Sample number
1 3 4 5 6 7 8 9
2 10 11 12
CL
x
+1σ
-1σ
-2σ
-3σ
+2σ
+3σ R
A
x
A
Zone 2


R
A
x
B
Zone 2
2
1


R
A
x
C
Zone 2
3
1


R
A
x
B
Zone 2
2
1


R
A
x
C
Zone 2
3
1


R
A
x
A
Zone 2


Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 59
Process Improvement
Methods for Generating New Ideas:
The 5W2H Approach
Brainstorming
Nominal Group Technique
Interviewing
Focus Groups
Quality Circles “Kaizen Teams”
Benchmarking.
.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 60
Process Improvement
Tools for Investigating the Presence of Quality Problems and
Their Causes
Check Sheet
Histogram
Scatter Diagram
Flow Chart
Cause-and-Effect Diagram
Pareto Chart
.
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 61
Figure 12.10. A Check Sheet and Corresponding Histogram
for Emergency Room Wait Times
Weeks
A
Wait time to
register >10
minutes
B
Registration
time > 5
minutes
C
Wait time for
MD > 15
minutes
1 /// //////
2 //// / /
3 ////// /// //////
4 / // /////
5 ////// // /////
0
1
2
3
4
5
6
Week 1 Week 2 Week 3 Week 4 Week 5
A
B
C
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 62
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0 5 10 15 20
Number of Infections per Month
Morbidity
Rate
Figure 12.11 Scatter Diagram
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 63
E.D. MD
Requests X-ray
Obtain Form
Hand Write
Patient
Demographic
Information
NO
YES
1
Physician
Completes Form
Computer-
Prepared Form
Available?
Figure 12.12 A Flow Chart for the X-Ray Order Process in an Emergency Department
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 64
Patient
Wait Too
Long
Equipment/Material
Rewards
People
Methods/Processes Functions
Structure
Tests not coordinated
Delays in ordering tests
Test Errors
Boring Environment
Lack of Supplies
Lack of ER Beds
Design is
not efficient
Lack of automated
system
Lab/Rad./ER
Depts. report
to different VPs
Lack of Feedback
Lack of incentives
Too many steps
Hospital room
not available if
admitted
Private MDs
not on site
Lack of
transporters
Figure 12.13 Cause and Effect Diagram
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 65
100%
75%
50%
25%
0
Lack of info.
to patient
Too many
steps
Delays in
test orders
Lack of
automation
Ineffective/
voluminous
documentation
Other
80%
Figure 12.14 Pareto Diagram
Chapter 12: Quantitatve
Methods in Health Care
Management Yasar A. Ozcan 66
The End

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chapter12.ppt

  • 1. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 1 Chapter 12. Quality Control UCL LCL Sample number 1 3 4 5 6 7 8 9 2 10 11 12 CL x +1σ -1σ -2σ -3σ +2σ +3σ R A x A Zone 2   R A x B Zone 2 2 1   R A x C Zone 2 3 1   R A x B Zone 2 2 1   R A x C Zone 2 3 1   R A x A Zone 2  
  • 2. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 2 Outline  Quality in Healthcare  Quality Experts  Quality Certification  TQM & CQI  Six-Sigma  Monitoring Quality through Control Charts – Control Charts for Attributes – Control Charts for Variables  Process improvement  Methods for Generating New Ideas  Tools for Investigation
  • 3. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 3 A Broad Definition. . .  Quality refers to the ability of a product or service to consistently meet or exceed customer expectations  quality in healthcare is evaluated from differing perspectives of providers, recipients and third- party payers.  Most clinicians accept the Institute of Medicine (1990) definition: “Quality is the extent to which health services for individuals and populations increase the likelihood of desired health outcomes and are consistent with current professional knowledge.”
  • 4. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 4 What is quality? You are a world renowned surgeon that has just completed a radical new surgical technique. There were few complications, largely due to the excellence of the hospital’s staff and technological capabilities. QUALITY?
  • 5. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 5 What is Quality? You are a patient who has just undergone radical new surgery. Although the surgery went without technical difficulties, your were upset at the doctor’s uncaring attitude. Furthermore, the nursing staff often failed to respond to your calls, and twice you were served meat despite the fact that you are a vegetarian. Also, there was a used bedpan that sat next to your bed for three days. QUALITY?
  • 6. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 6 A question of perspective  Quality of care depends upon who is making the assessment – Clinician-- technical components, adequate skills, resources, conditions – Patients-- outcomes, interpersonal processes, amenities, overall satisfaction – Health Facility Managers- appropriate and effective utilization – Community-- availability, access, reputations, general health status of community
  • 7. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 7 Quality Measurement  Clinicians-- cure rates, mortality, morbidity  Patients-- patient satisfaction surveys  Health facility managers-- cure rates, mortality, morbidity, intermediate process measures (patient falls, infection rates, medication errors, appropriate staffing, etc.)  Community-- area service distribution, insurance coverage, incidence and prevalence rates, etc.
  • 8. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 8 Figure 12.1 Quality Measurement Structure Process Outcome Inputs Conversion Process (Throughput) Outputs Patient, provider labor equipment supplies, etc. Various hospital and medical services transform poor health to wellness for patients (diagnosis, procedures, treatments) Treated Patient
  • 9. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 9 Quality Measurement Another way to look at the maintenance of quality is how mistakes are to be avoided – design mistake-proof processes across the whole spectrum of the care, to reduce undesired outcomes. Variance in diagnostic and therapeutic interventions and the associated errors hamper the delivery of safe, effective patient care and add to poor outcomes. To minimize the variation and the errors – sometimes euphemistically called “quality gaps” – and work toward completely eliminating them are major goals for healthcare systems. Quality Gaps
  • 10. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 10 Quality Measurement Chassin (1998) classifies the underlying causes of “quality gaps” into three categories: 1) Over-utilization. When the potential benefit of a therapy is less than its risk, overuse of health services affects the quality of care. Pressures for overuse of services may come from either providers or patients. 2) Under-utilization. A patient’s lack of insurance or insurance that has high co-payments and deductibles can cause under-utilization of necessary health care. 3) Miss-utilization. Avoidable complications, negligent care, mistakes, and mishaps create miss- utilization of services. Healthcare providers who generate such conditions harm the quality of patient care and produce poor outcomes; they also waste the organization’s resources and increase lengths of stay. Quality Gaps
  • 11. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 11 Quality Measurement Healthcare providers do have an arsenal of methods to deal effectively with the problems affecting quality of care. They include the programs called quality control (QC), total quality management (TQM), continuous quality improvement (CQI), reengineering, and Six-Sigma. All these programs include data gathering, analysis and statistical monitoring to identify the problem and its cause. Nevertheless, the crux of the solution to quality problems lies in changing human behavior, changing minds to perform care in new ways.
  • 12. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 12 Quality Experts  Deming-- poor quality caused by the system, not employees; management’s responsibility to correct system;” use 14 points to reduce variation caused by special causes (correctable) and not common (random) causes of variation.  Juran-- 80% of defects are controllable; three elements: quality planning, quality control, and continual quality improvement  Crosby-- zero defects; quality is free  Isikawa-- cause and effect diagrams, quality circles
  • 13. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 13  Organizations can earn awards or achieve certification/accreditation by international organizations or by their own trade organizations; for instance, hospitals are evaluated periodically by the Joint Commission on Accreditation of Healthcare Organizations (JCAHO).  For the medical group practices, the Medical Group Management Association (MGMA) is the principal voice. MGMA leads the profession and assists members through information, education, networking and advocacy” (MGMA, 2004).  Quality is always a major concern in those advocacy and accreditation bodies. Quality Certification
  • 14. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 14 Quality Certification  ISO 9000  Set of international standards on quality management and Quality assurance, critical to international Business  ISO 9000 series standards, briefly, require firms to document their quality-control systems at every step (incoming raw materials, product design, in-process monitoring and so forth) so that they’ll be able to identify those areas that are causing quality problems and correct them.  ISO 9000 requires companies to document everything they do that affects the quality of goods and services. – Hierarchical approach to documentation of the Quality Management System
  • 15. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 15 Total Quality Management  A philosophy that involves everyone in an organization in the quest for quality, with customer satisfaction as the driving force  TQM involves: – finding what customers want – designing services to meet customer needs – designing mistake proof delivery process “pakayoke” – monitoring results and continuous improvement
  • 16. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 16 TQM, cont.  TQM requires: – continual improvement – competitive benchmarking – employee empowerment – team approaches – knowledge of tools  Quality at the source-- each worker responsible for his/her own work  Quality function deployment-- involve customers in service design
  • 17. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 17 Controlling Quality  Quality control focuses on the conversion of inputs into outputs, i.e., the processes  Goal is to reduce the need for inspection of control efforts  Quality assurance efforts occurring during production of services are referred to as statistical process control
  • 18. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 18 Plan Do Act Check Figure 12.2 The Deming Wheel/Shewhart Cycle
  • 19. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 19 Continuous Quality Improvement  A philosophy seeking to make never-ending improvements to the process of converting inputs into outputs  Kaizen-- Japanese term referring to CI  Environment must be conducive to CI – appropriate vision statement, strategies, tactics – management style encouraging trust, openness – adherence to stated philosophy – reward/incentive systems
  • 20. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 20 The CQI is a detailed version of a PDSA cycle that comprises: 1) selecting a process that needs an improvement 2) studying and documenting the current process seeking ways to improve it 3) designing an improved process 4) implementing the new process 5) monitoring and evaluation 6) documenting the process if it worked successfully and publicizing it through the healthcare organization 7) if it did not achieve its goals, re-starting from step 1. Continuous Quality Improvement
  • 21. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 21 Six-Sigma •Six- Sigma is one of the latest quality improvement concepts to have emerged during the 1990’s. Its name comes from the measure of variation from the normal distribution (six standard deviations). •Adopting a six-sigma strategy as a quality goal sets tolerance levels for errors (defectives) to levels that occur only 3.4 times per million observations. •The defect rates in healthcare can be defined in such distinct areas as public health, inpatient care, ambulatory care, and so on.
  • 22. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 22 Six-Sigma Healthcare organizations have reduced the deaths caused by anesthesia from 25-50 per million cases to 5 per million cases since the 1980s through improved monitoring techniques, adaptation of practice guidelines, and other systematic approaches to reduce errors. This is one area that comes very close to six sigma standards (Chassin, 1998).
  • 23. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 23 Six-Sigma Deployment of six-sigma to improve the quality of healthcare and delivery performance can be considered in the following areas: a) Clinical excellence b) Service delivery c) Service costs, and d) Patient satisfaction. The deployment can use either of these methodological sequences: DMAIC: define, measure, analyze, improve, and control DMADV: define, measure, analyze, design, and verify. DMAIC is generally used to improve existing systems that have fallen the below six-sigma levels, DMADV is used to design and develop new processes or products at six-sigma levels (Stahl, Shultz, and Pexton, 2003).
  • 24. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 24 Six-Sigma The essence of six-sigma methodologies is both improvement of the knowledge and capability of employees, and also changes behavior through training. Thus six-sigma employs a classification system that identifies education and training for employees, project managers and executives. Emulating karate honors, certification is granted at Green Belt (GB), Black Belt (BB) and Master Black Belts (MBB) levels.
  • 25. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 25 Six-Sigma Green Belts (GBs) are the employees who have taken the training courses on implementing the projects. Black Belts (BBs) are the project leaders, whose training may be more intensive; they may complete several projects a year depending upon their size and scope. Master Black Belts (MBBs) are generally assigned to an area that needs improvement (for example, human resources), to ensure that objectives are set, targets are identified, plans are made, and resources are secured to implement the projects in their assigned area. MBBs may oversee many six-sigma projects at a time, working with various BBs.
  • 26. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 26 Six-Sigma Six-sigma projects require BBs and MBBs to have expertise in basic statistical tools such as Pareto Diagrams, descriptive and higher level statistics including regression, and statistical modeling techniques as well as control processes. In addition to statistical concepts, they are expected understand project management, finance, leadership, measurement through socio-metric (survey) analysis, reliability and validity.
  • 27. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 27 Six-Sigma Examples of successful six-sigma deployments in healthcare include: •reduction of emergency room diversions •fewer errors in operating rooms’ cart materials •reduced bloodstream infections in an ICU, and •improved radiology turnaround time (Stahl, Shultz, and Pexton, 2003).
  • 28. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 28 Quality Measurement and Control Techniques Process Variability In the delivery of health care, there are many occasions when an error can happen in the tasks performed by various clinical staff. Often the same task may not even be performed the same way for all patients, though minor alterations within defined limits can be acceptable. When provider performance falls beyond acceptable limits, the errors that occur require investigation and correction. In order to detect noteworthy variations in process, or tendencies that may cause unacceptable levels of errors, healthcare managers must monitor the processes for quality, using various charts. The intent of the monitoring is to distinguish between random and non-random variation.
  • 29. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 29 Quality Measurement and Control Techniques Process Variability The common variations in process variability that are caused by natural incidences are in general not repetitive, but various minor factors due to chance and are called random variation. If the cause of variation is systematic, not natural, and the source of the variation is identifiable, the process variation is called non-random variation. In healthcare, non-random variation may occur by not following procedures, using defective materials, fatigue, carelessness, or not having appropriate training or orientation to the work situation, among many reasons.
  • 30. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 30 Quality Measurement and Control Techniques Process Variability Process variation is the range of natural variability in a process for which healthcare managers use control charts to monitor the measurements. If the natural variability or the presence of random variation exceeds tolerances set by control charts, then the process is not meeting the design specifications.
  • 31. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 31 Set design specifications for process capability Process Variability UCL LCL Process variability meets and exceeds specifications Process variability does not meet design specifications Figure 12.3 Process Capability
  • 32. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 32 Figure 12.4 Control Limits, Random and Nonrandom Sample Observations Upper Control Limit (UCL) Lower Control Limit (LCL) Process Mean Sample number 1 3 4 5 6 7 8 9 2 10 11 12 Non-random α/2 α/2 95.5% +2σ -2σ
  • 33. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 33 Control Charts for Attributes When process characteristics can be counted, attribute-based control charts are the appropriate way to display the monitoring process. If the number of occurrences per unit of measure can be counted, or there can be a count of the number of bad occurrences but not of non-occurrences, then a c-chart is the appropriate tool to display monitoring. Counting also can occur for a process with only two outcomes, good or bad (defective); in such cases p-chart is the appropriate control chart.
  • 34. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 34 Control Charts for Attributes: c-Chart c z c UCL   c z c LCL  
  • 35. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 35 Control Charts for Attributes: c-Chart Example 12.1 The number of infections from the Intensive Care Unit (ICU) at the ABC Medical Center over a period of 24 months is obtained. These numbers are the counts of stool assay positive for toxin, segregated by month. The patient population and other external factors such as change in provider have been stable. Months Infections in ICU Year 1 Year 2 January 3 4 February 4 3 March 3 6 April 4 3 May 3 4 June 4 3 July 5 5 August 3 6 September 4 3 October 3 3 November 7 6 December 4 3 Total 47 49 The nurse manager who serves on the quality team wants to discover whether the infections are in control within 95.5% confidence limits.
  • 36. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 36 Control Charts for Attributes: c-Chart Solution If we consider each month as a sample of bad quality outcomes, for 24 samples we have a total of 96 quality defects (infections), and the average would be: c = 96/24 = 4.0. Since the z-value for 95.5% confidence level is equal to 2, using formulas we obtain: . 8 2 * 2 4 4 2 4        c z c UCL . 0 2 * 2 4 4 2 4        c z c LCL
  • 37. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 37 Figure 12.5 ABC Medical Center Infection Control Monitoring UCL=8 LCL=0 Sample number 1 3 4 5 6 7 8 9 2 10 11 12 13 14 15 16 17 18 19 20 22 21 23 24 Infections per month 4  c
  • 38. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 38 Control Charts for Attributes: p-Chart The proportion of defects in a process can be monitored using a p-chart that has binomial distribution as its theoretical base. The center of the p-chart represents the average for defects and LCL and UCL are calculated as: n p p z p ) 1 ( UCL    n p p z p ) 1 ( LCL   
  • 39. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 39 Example 12.2 The indicator Family Satisfaction, which is part of the National Hospice and Palliative Care Organization’s survey, reflects the percentage of respondents who would not recommend the hospice services to others. The following data are from Holistic Care Corporation’s completed surveys from 200 families each month during a year, showing the number of respondents each month who expressed dissatisfaction with the organization’s services. Control Charts for Attributes: p-Chart Months Dissatisfied Patient Families Percent Dissatisfied January 12 0.060 February 14 0.070 March 16 0.080 April 14 0.070 May 25 0.125 June 14 0.070 July 15 0.075 August 16 0.080 September 14 0.070 October 14 0.070 November 24 0.120 December 14 0.070 Total 192 0.080 The manager in charge of quality wishes to construct a control chart for this data within 95.5% confidence intervals.
  • 40. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 40 Solution: First, we need to estimate the proportion mean, Total number of quality infractions 192 192 = -------------------------------------------- = ----------- = ------- = .08 Total number of observations 12 (200) 2400 Since the z value for the 95.5% confidence level is equal to 2.0, using formulas we obtain: Control Charts for Attributes: p-Chart p . 118 . 0 2 08 . 200 ) 08 . 1 ( 08 .     UCL . 042 . 0 2 08 . 200 ) 08 . 1 ( 08 .     LCL
  • 41. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 41 Figure 12.6 Holistic Care Corporation’s Quality Monitoring UCL=.118 LCL=0.042 Sample number 1 3 4 5 6 7 8 9 2 10 11 12 Proportion of Families Dissatisfied 08 .  p
  • 42. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 42 Figure 12.7 Use of Mean and Range Charts UCL LCL Process Mean Range indicator Mean indicator UCL LCL Stable mean, increasing range process Increasing mean, stable range process
  • 43. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 43 Mean Charts - Standard Deviation Approach. Control Charts for Variables  z x UCL   In general the population standard is unknown, and so the average of sample means ) (x and the standard deviation of sample distribution σ x are used to construct the confidence limits as: x  z x LCL   x where σ x n s/  .
  • 44. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 44 Example 12.3 With a time-motion study, the IV startup process has been examined in a medical center nursing unit for five weekdays to determine whether in the future, additional training of nurses is required. Each day 9 new patients’ IV startups were observed and the measurements recorded in minutes, as shown below. Construct 99.7% (z = 3) confidence limits for IV startup times. Control Charts for Variables: Mean Chart, σ Method Observation Day-1 Day-2 Day-3 Day-4 Day-5 1 5.1 4.9 5.5 6.1 6.0 2 5.4 5.7 5.6 5.8 5.2 3 5.5 6.3 5.3 5.9 6.3 4 5.8 7.5 4.9 6.0 5.0 5 5.6 5.8 5.2 6.2 5.5 6 5.8 5.9 5.4 5.7 5.1 7 5.3 5.5 6.4 4.8 5.9 8 4.9 5.8 7.5 6.3 5.3 9 6.2 5.5 5.8 5.9 4.8
  • 45. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 45 Solution Observation means for each day (sample) are calculated and are shown in the last rows of the following table. Control Charts for Variables: Mean Chart, σ Method x Sample Day-1 Day-2 Day-3 Day-4 Day-5 5.51 5.88 5.73 5.86 5.46 s 0.6 x = (5.51+5.88+5.73+5.86+5.46) ÷ 5 = 5.69. with z = 3, n = 9 observations per sample (day), and s = 0.6, we obtain: . 29 . 6 ) 2 . 0 ( 3 69 . 5 ) 9 / 6 . 0 ( 3 69 . 5      UCL . 09 . 5 ) 2 . 0 ( 3 69 . 5 ) 9 / 6 . 0 ( 3 69 . 5      LCL
  • 46. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 46 Mean Charts - Range Approach. Control Charts for Variables Another way to construct a mean chart is to use the average of sample distribution ranges,. This approach requires a factor to calculate the dispersion of the control limits. . R A x UCL 2   R A x UCL 2   Where A2 is a factor from Table 12.1
  • 47. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 47 Table 12.1 Factors for Determining Control Limits for Mean and Range Charts (for 3-sigma or 99.7% confidence level) Sample Size n Factor for Mean Chart, A2 Factors for Range Chart LCL, D3 UCL, D4 2 1.88 0 3.27 3 1.02 0 2.57 4 0.73 0 2.28 5 0.58 0 2.11 6 0.48 0 2.00 7 0.42 0.08 1.92 8 0.37 0.14 1.86 9 0.34 0.18 1.82 10 0.31 0.22 1.78 Source: p. 143, Operations Management by Rusell & Taylor, 1995.
  • 48. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 48 Example 12.4 During 5 weekdays, each day the number minutes spent for each of 10 patient registration operations were observed in a time study as follows: Control Charts for Variables: Mean Chart, Range Method Observation Day-1 Day-2 Day-3 Day-4 Day-5 1 10.2 10.3 8.9 9.5 10.5 2 9.7 10.9 10.5 9.7 10.2 3 10.3 11.1 8.9 10.5 10.3 4 8.9 8.9 10.5 9.8 10.9 5 10.5 10.5 9.8 8.9 11.1 6 9.8 9.7 10.2 10.5 9.8 7 10.0 8.9 8.9 10.4 9.5 8 11.3 10.5 10.5 8.9 9.7 9 10.7 9.8 9.7 10.5 10.5 10 9.8 11.3 10.5 9.8 8.8
  • 49. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 49 Solution The overall mean for each sample and range is required to apply the formulas, using the range approach. Here each day is considered as a sample. The range is calculated by taking the difference between the maximum and minimum of each sample (day). The, mean for each day also is calculated and shown as follows: Control Charts for Variables: Mean Chart, Range Method x Sample Day-1 Day-2 Day-3 Day-4 Day-5 Maximum 11.3 11.3 10.5 10.5 11.1 Minimum 8.9 8.9 8.9 8.9 8.8 Range 2.4 2.4 1.6 1.6 2.3 10.12 10.19 9.84 9.85 10.13 x = (10.12+10.19+9.84+9.85+10.13) ÷ 5 = 10.03. R = (2.4+2.4+1.6+1.6+2.3) ÷ 5 = 2.06. UCL = 10.03 + 0.31 (2.06) = 10.67. LCL = 10.03 – 0.31 (2.06) = 9.39.
  • 50. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 50 Range Charts Control Charts for Variables Process dispersion is best monitored by range charts. The control limits for range charts are constructed using factors. To calculate LCL, factor score D3 is obtained from a factor chart (Table 12.1) based on the number of observations in the sample distributions. Similarly, to calculate UCL, factor score D4 is required. Control limits for range charts using these factor scores are then constructed as follows: . R D UCL 4  R D LCL 3 
  • 51. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 51 Example 12.5 Use the information provided in example 12.4 to construct a range chart. Solution For n = 10, D3 and D4 from Table 12.1 are 0.22 and 1.78, respectively. Using formulas we obtain: Control Charts for Variables: Range Chart UCL = 1.78 (2.06) = 3.67. LCL = .22 (2.06) = 0.45.
  • 52. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 52 Investigation of Control Chart Patterns A pattern in a control chart described by a sequence of observations that have similar characteristics is called a “run.” A simple classification of sample observations with respect to the center line that identify consecutive patterns is called an Above/Below run, or A/B run. Up (U) and down (D) runs is another way to classify and observe patterns. To classify sample observations as U or D, the first observation is used as a reference point . Run-Based Pattern Tests.
  • 53. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 53 Figure 12.8 Identification of Runs UCL LCL Sample number 1 3 4 5 6 7 8 9 2 10 11 12 A B B B B B A A A A A A D D D D D D U U D U U * Observed runs 6 5 1 2 4 3 6 5 1 2 3 5 4 CL
  • 54. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 54 Investigation of Control Chart Patterns Control chart patterns identified by runs require statistical testing of whether the runs are within expectations and hence the patterns are random, or beyond expectations and hence non-randomness is present. It has been shown that runs are distributed approximately normally (Stevenson, 2002, p.436) and using the z-test the significance of too few or too many observed runs can be determined as follows: . Run-Based Pattern Tests. runs of deviation dard S runs Expected runs Observed z tan   A z-value within ±2, which provides 95.5% confidence level, would show that the runs are random; however, beyond these values ≤ ±2 ≥, a non-random presence would be shown.
  • 55. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 55 Investigation of Control Chart Patterns It is necessary to calculate the expected runs and their standard deviations. The formulas for expected A/B or U/D runs and their standard deviations are as follows: . Run-Based Pattern Tests. 1 2 ) ( /   N run E B A 4 1 ) ( /   N run B A  3 1 2 ) ( /   N run E D U 90 29 16 ) ( /   N run D U 
  • 56. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 56 Example 12.6 Determine the presence/absence of non-randomness for the example presented in Figure 12.8, with 95.5% confidence limits. Solution The example has twelve observations, so N=12. Using the formulas we get: Investigation of Control Chart Patterns 0 . 7 1 2 12 ) ( /    B A run E 66 . 1 75 . 2 4 11 4 1 12 ) ( /      B A run  67 . 7 3 1 ) 12 * 2 ( ) ( /    D U run E 35 . 1 81 . 1 90 163 90 29 ) 12 * 16 ( ) ( /      D U run  60 . 0 66 . 1 7 6 /     B A z 98 . 1 35 . 1 67 . 7 5 /     D U z conclude that U/D runs exhibit randomness. conclude that the A/B runs exhibit randomness.
  • 57. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 57 Investigation of Control Chart Patterns An alternative method that is often used by quality control software packages is called the “zone test.” The essence of the zone test rests on deviation from the center line by 1-sigma, 2- sigma, or 3-sigma limits. Zone C, zone B and Zone A are identified by these limits, respectively. To create the zones, the formulas for constructing mean chart with range approach formulas are used. Those formulas, presented earlier, use A2 from Table 12.1, and the values for this table were calculated for 3-sigma levels (or 99.7% confidence level). Thus, in constructing the zones, one must reduce the A2 factor proportionately, according to the sigma level. Since A2 is designated for 3-sigma, for 2-sigma 2/3 of A2, and for 1-sigma 1/3 of A2 would be appropriate. The zone formulas can be written as: . Zone Tests. R A x A Zone 2   R A x B Zone 2 2 1   R A x C Zone 2 3 1  
  • 58. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 58 Figure 12.9 Zone test UCL LCL Sample number 1 3 4 5 6 7 8 9 2 10 11 12 CL x +1σ -1σ -2σ -3σ +2σ +3σ R A x A Zone 2   R A x B Zone 2 2 1   R A x C Zone 2 3 1   R A x B Zone 2 2 1   R A x C Zone 2 3 1   R A x A Zone 2  
  • 59. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 59 Process Improvement Methods for Generating New Ideas: The 5W2H Approach Brainstorming Nominal Group Technique Interviewing Focus Groups Quality Circles “Kaizen Teams” Benchmarking. .
  • 60. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 60 Process Improvement Tools for Investigating the Presence of Quality Problems and Their Causes Check Sheet Histogram Scatter Diagram Flow Chart Cause-and-Effect Diagram Pareto Chart .
  • 61. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 61 Figure 12.10. A Check Sheet and Corresponding Histogram for Emergency Room Wait Times Weeks A Wait time to register >10 minutes B Registration time > 5 minutes C Wait time for MD > 15 minutes 1 /// ////// 2 //// / / 3 ////// /// ////// 4 / // ///// 5 ////// // ///// 0 1 2 3 4 5 6 Week 1 Week 2 Week 3 Week 4 Week 5 A B C
  • 62. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 62 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0 5 10 15 20 Number of Infections per Month Morbidity Rate Figure 12.11 Scatter Diagram
  • 63. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 63 E.D. MD Requests X-ray Obtain Form Hand Write Patient Demographic Information NO YES 1 Physician Completes Form Computer- Prepared Form Available? Figure 12.12 A Flow Chart for the X-Ray Order Process in an Emergency Department
  • 64. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 64 Patient Wait Too Long Equipment/Material Rewards People Methods/Processes Functions Structure Tests not coordinated Delays in ordering tests Test Errors Boring Environment Lack of Supplies Lack of ER Beds Design is not efficient Lack of automated system Lab/Rad./ER Depts. report to different VPs Lack of Feedback Lack of incentives Too many steps Hospital room not available if admitted Private MDs not on site Lack of transporters Figure 12.13 Cause and Effect Diagram
  • 65. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 65 100% 75% 50% 25% 0 Lack of info. to patient Too many steps Delays in test orders Lack of automation Ineffective/ voluminous documentation Other 80% Figure 12.14 Pareto Diagram
  • 66. Chapter 12: Quantitatve Methods in Health Care Management Yasar A. Ozcan 66 The End