Chapter 5’s Case StudyNew Century Wellness Group offers a holistic approach to healthcare with an emphasis on
preventive medicine as well as traditional medical care. In your role as an IT consultant, you will
help New Century develop a new information system.
Background
You began the systems analysis phase by conducting interviews, reviewing existing reports,
and observing office operations. (Your instructor may provide you with a sample set of interview
summaries.)
The New Century medical team performs services and medical procedures, which are coded
according to the American Medical Association’s Current Procedure Terminology (CPT). CPT
codes consist of five numeric digits and a two-digit suffix, and most insurance payers require the
codes to be included with billing information.
The new system must be able to handle the new ICD-10 procedure coding system, which will be
required by the Centers for Medicare & Medicaid Services (CMS) beginning October 1, 2014.
ICD-10 codes consist of seven alphanumeric characters, which can be electronically transmitted
and received. New Century’s information system must interface with 25 California health
insurance providers. The new system represents an opportunity for significant cost saving for
New Century, and more convenience for patients, who will be able to go online to update
medical information, schedule appointments, and request medical records.
During your fact-finding, you learned that the clinic requires various reports, as follows:
• Daily appointment list for each provider. The list shows all scheduled appointment times,
patient names, and services to be performed, including the procedure code and
description.
• Daily report call list, which shows the patients who are to be reminded of their next day’s
appointments. The call list includes the patient name, telephone number, appointment
time, and provider name.
• Weekly provider report that lists each of the providers and the weekly charges generated,
plus a month-to-date (MTD) and a year-to-date (YTD) summary as well as profit
distribution data for the partners.
• Monthly patient statement, which includes the statement date, head of household name
and address, previous month’s balance, total household charges MTD, total payments
MTD, and the current balance. The bottom section of the statement shows activity for the
month in date order. For each service performed, a line shows the patient’s name, the
service date, the procedure code and description, and the charge. The statement also
shows the date and amount of all payments and insurance claims. When an insurance
payment is received, the source and amount are noted on the form. If the claim is denied
or only partially paid, a code is used to explain the reason. A running balance appears at
the far right of each activity line.
• Weekly Insurance Company Report.
• Monthly Claim Status Summary.
In addition to these reports, the office staff would like automated e-mail and text messaging
capability for sending reminders to patients when it is time to schedule an appointment. Data
also needs to be maintained on employers who participate in employee wellness programs. This
information can be used for marketing purposes throughout the year. Finally, the new system
needs to track employee schedules, attendance, vacation time, and paid time off.
Now you are ready to organize the facts and prepare a system requirements document that
represents a logical model of the proposed system. Your tools will include DFDs, a data
dictionary, and process descriptions.
Analysis
Capstone Case: New Century Wellness Group
Tasks
1. Prepare a context diagram for New Century’s information system.
2. Prepare a diagram 0 DFD for New Century. Be sure to show numbered processes for
handling appointment processing, payment and insurance processing, report processing,
and records maintenance. Also, prepare lower-level DFDs for each numbered process.
3. Prepare a list of data stores and data flows needed for the system. Under each data store,
list the data elements required.
4. Prepare a data dictionary entry and process description for one of the system’s functional
primitives.
CASE Tool
Chapter 5
Data and Process Modeling
Learning Objectives (1 of 2)
•After this chapter, you will be able to:
• Describe the relationship between logical and
physical models
• Explain data flow diagrams
• Draw the four basic data flow diagram
symbols
• Explain the six guidelines used when drawing
data flow diagrams
• Draw context diagrams
• Draw diagram 0 data flow diagrams
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Learning Objectives (2 of 2)
• Draw lower-level data flow diagrams
• Explain how to level and balance data flow
diagrams
• Create a data dictionary
• Apply process description tools in modular
design
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Logical Versus Physical Models (1
of 2)
•Logical model
• Shows what the system must do, regardless of
how it will be implemented physically
•Physical model
• Describes how the system will be constructed
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Logical Versus Physical Models (2
of 2)
•Many analysts follow a four-model
approach
• Physical model of the current system
• Logical model of the current system
• Logical model of the new system
• Physical model of the new system
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Flow Diagrams
•Systems analysts use graphical
techniques to describe an information
system
• Data flow diagram (DFD)
• Uses various symbols to show how the system
transforms input data into useful information
• Shows how data moves through an information
system but does not show program logic or
processing steps
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Flow Diagram Symbols (1 of
9)
•Four basic symbols represent processes,
data flows, data stores, and entities
FIGURE 5-1 Data flow
diagram symbols, symbol
names, and examples of the
Gane and Sarson and
Yourdon symbol sets
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Flow Diagram Symbols (2 of
9)
•Process symbols
• Process receives input data and produces
output
• Contains business logic that transforms the
data
• Process name identifies a specific function
• In DFDs, a process symbol can be referred to
as a black box
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Flow Diagram Symbols (3 of
9)
•Data flow
symbols
• Line with a single
or double
arrowhead
FIGURE 5-3 Examples of
correct combinations of data
flow and process symbols
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Flow Diagram Symbols (4 of
9)
•Data flow and process combinations that
must be avoided
• Spontaneous generation
• Black holes
• Gray holes
FIGURE 5-4 Examples of incorrect combinations of data flow and
process symbols. APPLY INSURANCE PREMIUM has no input
and is called a spontaneous generation process. CALCULATE
GROSS PAY has no outputs and is called a black hole process.
CALCULATE GRADE has an input that is obviously unable to
produce the output. This process is called a gray hole.
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Flow Diagram Symbols (5 of
9)
•Data store symbol
• Represent data that the system stores
• DFD does not show the detailed contents of a
data store
• Specific structure and data elements are defined in
the data dictionary
• A data store must be connected to a process
with a data flow
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Flow Diagram Symbols (6 of
9)
•Entity symbol
• Shows how the system interfaces with the
outside world
• DFD shows only external entities that provide
data to the system or receive output
• DFD entities also are called terminators because
they are data origins or final destinations
• Source and sink entities
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Flow Diagram Symbols (7 of
9)
FIGURE 5-7 Examples of correct uses of external entities in a data flow diagram.
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Flow Diagram Symbols (8 of
9)
FIGURE 5-8 Examples of incorrect uses of external entities. An external entity must be connected
by a data flow to a process, and not directly to a data store or to another external entity.
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Flow Diagram Symbols (9 of
9)
•Using DFD symbols
FIGURE 5-9 Examples of correct
and incorrect uses of data flows.
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Drawing Data Flow Diagrams (1 of
2)
•Graphical model is created based on factfinding results
• Review guidelines for drawing DFDs
• Apply guidelines and create a set of DFDs
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Drawing Data Flow Diagrams (2 of
2)
•Guidelines
• Draw the context diagram so that it fits on one
page
• Use the name of the information system as the
process name in the context diagram
• Use unique names within each set of symbols
• Do not cross lines
• Provide a unique name and reference number
for each process
• Ensure that the model is accurate, easy to
understand, and meets the needs of its users
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Drawing a Context Diagram
•First step in constructing a set of DFDs
FIGURE 5-11 Context diagram
DFD for an order system.
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Drawing a Diagram 0 DFD
•Shows the detail inside the black box
FIGURE 5-13 Diagram 0
DFD for the order system.
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Drawing Lower-Level DFDs (1 of
5)
•Leveling and balancing techniques are used
FIGURE 5-14 Diagram 1
DFD shows details of the
FILLORDER process in the
order system
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Drawing Lower-Level DFDs (2 of
5)
FIGURE 5-15 This diagram
does not show the symbols that
connect to data flows entering
or leaving FILL ORDER on the
context diagram.
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Drawing Lower-Level DFDs (3 of
5)
FIGURE 5-16 The order system diagram 0 is
shown at the top of the figure, and exploded
diagram 3 DFD (for the APPLY PAYMENT
process) is shown at the bottom. The two DFDs
are balanced because the child diagram at the
bottom has the same input and output flows as
the parent process 3 shown at the top.
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Drawing Lower-Level DFDs (4 of
5)
FIGURE 5-17 Example of a parent DFD diagram, showing process 0 as a black box.
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Drawing Lower-Level DFDs (5 of
5)
FIGURE 5-18 In the next level of detail, the process 0 black box reveals three processes, two data
stores, and four internal data flows — all of which are shown inside the dashed line.
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Dictionary (1 of 11)
•Central storehouse of information about a
system’s data
• An analyst uses the data dictionary to collect,
document, and organize specific facts about a
system
• Defines and describes all data elements and
meaningful combinations of data elements
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Dictionary (2 of 11)
•Data element (i.e., data item or field)
• Smallest piece of data that has meaning within
an information system
• Combined into records (i.e., data structures)
• Record: meaningful combination of related data
elements that is included in a data flow or retained
in a data store
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Dictionary (3 of 11)
•Using CASE tools for documentation
• More complex the system, more difficult it is to
maintain full and accurate documentation
• Modern CASE tools simplify the task
• A CASE repository ensures data consistency
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Dictionary (4 of 11)
•Documenting the data elements
• Every data element in the data dictionary
should be documented
• Objective: provide clear, comprehensive
information about the data and processes that
make up a system
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Dictionary (5 of 11)
•Recorded and described attributes
• Data element name and label
• Alias
• Type and length
• Default value
• Acceptable values
• Source
• Security
• Responsible user(s)
• Description and comments
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Dictionary (6 of 11)
•Documenting the data flows
• Data flow name or label
• Description
• Alternate name(s)
• Origin
• Destination
• Record
• Volume and frequency
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Dictionary (7 of 11)
•Documenting the data stores
• Data store name or label
• Description
• Alternate name(s)
• Attributes
• Volume and frequency
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Dictionary (8 of 11)
•Documenting the processes
• Process name or label
• Description
• Process number
• Process description
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Dictionary (9 of 11)
•Documenting the entities
• Entity name
• Description
• Alternate name(s)
• Input data flows
• Output data flows
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Dictionary (10 of 11)
•Documenting the records
• Record or data structure name
• Definition or description
• Alternate name(s)
• Attributes
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Data Dictionary (11 of 11)
•Data dictionary reports
• Alphabetized list of all data elements
• Report describing each data element and
indicating the user or department
• Report of all data flows and data stores that
use a particular data element
• Detailed reports showing all characteristics of
data elements, records, data flows, processes,
or any other selected item stored in the data
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Process Description Tools in
Modular Design (1 of 6)
• Documents the details of a functional
primitive and represents a specific set of
processing steps and business logic
• Typical tools: structured English, decision tables,
and decision trees
• Process descriptions in object-oriented
development
• O-O analysis combines data and processes that
act on the data into objects, and similar objects
can be grouped together into classes
• O-O processes are called methods
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Process Description Tools in
Modular Design (2 of 6)
•Modular design
• Based on combinations of logical structures
(i.e., control structures), which serve as
building blocks for the process
• Sequence
• Selection
• Iteration
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
Process Description Tools in
Modular Design (3 of 6)
•Structured English
• Subset of standard English that describes
logical processes clearly and accurately
• Use only the three building blocks of sequence,
selection, and iteration
• Use indentation for readability
• Use a limited vocabulary
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Process Description Tools in
Modular Design (4 of 6)
•Decision tables
• Logical structure that shows every
combination of conditions and outcomes
• Number of rules doubles each time a condition
is added
• Best way to describe a complex set of
conditions
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Process Description Tools in
Modular Design (5 of 6)
FIGURE 5-35 In this version, dashes have been added to indicate that a condition is not
relevant. At this point, it appears that several rules can be combined.
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Process Description Tools in
Modular Design (6 of 6)
•Decision trees
• Graphical representation of conditions,
actions, and rules found in a decision table
FIGURE 5-36 This example is based on the same
Sales Promotion Policy shown in the decision
tables in Figures 5-34 and 5-35 on the previous
page. Like a decision table, a decision tree shows
all combinations of conditions and outcomes. The
main difference is the graphical format, which many
viewers find easier to interpret
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Summary
• Structured analysis tools
• Used to develop a logical model during one
systems analysis phase and a physical model
during the systems design phase
• Data and process modeling
• Main tools: DFDs, data dictionary, and process
description
• Each functional primitive process is
documented
• Structured English, decision tables, and decision
trees
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permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
