Mini Case:Capstone Case: New Century Wellness Group
New 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.
Tasks
- (30 pts) Prepare a context diagram for New Century’s information system. (Follow the textbook standards for diagram. Please see Fig 5-12)
- (45 pts) Prepare a diagram 0 DFD for New Century (See Fig 5-13). 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 two numbered process. (Follow the textbook standards for diagram. Please see Fig 5-14)
- (25 pts) Prepare a list of data stores and data flows needed for the system. Under each data store, list the data elements required. (Please read section 5.6 carefully not to miss any items. Please note that you don’t need to use any special software to create this list)
Chapter 5
Data and Process Modeling
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Describe data and process modeling
concepts and tools, including data flow
diagrams, a data dictionary, and process
descriptions
Describe the symbols used in data flow
diagrams and explain the rules for their use
Draw data flow diagrams in a sequence,
from general to specific
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Explain how to level and balance a set of data
flow diagrams
Describe how a data dictionary is used and
what it contains
Use process description tools, including
structured English, decision tables, and
decision trees
Describe the relationship between logical and
physical models
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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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or duplicated, or posted to a publicly accessible website, in whole or in part.
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
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or duplicated, or posted to a publicly accessible website, in whole or in part.
A data flow diagram (DFD) shows how data
moves through an information system but
does not show program logic or processing
steps
A set of DFDs provides a logical model that
shows what the system does, not how it does
it
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or duplicated, or posted to a publicly accessible website, in whole or in part.
DFD Symbols
◦ Four basic symbols represent processes, data flows,
data stores, and entities
◦ Gane and Sarson: Used in data
flow diagrams
Processes, data flows,
data stores, and external
entities all have a unique symbol
◦ Yourdon: Used in data flow
diagrams
FIGURE 5-1 Data flow diagram symbols, symbol names, and
examples of the Gane and Sarson and Yourdon symbol sets
Processes, data flows, data stores, and external entities each
have a unique symbol
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Process Symbol
• Must have at least one input
and at least one output
• Contains business logic that
transforms the data
• Process name identifies its
function (verb)
• Examples” : “apply rent
payment” or “calculate
commission
• In DFDs, a process symbol
can be referred to as a black
box
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or duplicated, or posted to a publicly accessible website, in whole or in part.
Data Flow Symbol
◦ Represents one or more
data items
◦ The symbol for a data
flow is a line with a single
or double arrowhead
FIGURE 5-3 Examples of correct combinations of data flow and process symbols
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Data Flow Symbol
◦ Following data flow and process combinations 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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Data Store symbol
• Represent data that the system
stores
•
•
A DFD does not show the detailed
contents of a data store — the 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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FIGURE 5-6 Examples of incorrect
uses of data store symbols: Two data
stores cannot be connected by a data
flow without an intervening process,
and each data store should have an
outgoing and incoming data flow
FIGURE 5-5 Examples of correct
uses of data store symbols in a data
flow diagram
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•
•
•
•
Entity Symbol
Shows how the system interfaces
with the outside world
A DFD shows only external entities
that provide data to the system or
receive output from the system
DFD entities also are called
terminators because they are data
origins or final destinations
Each entity must be connected to a
process by a data flow
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or duplicated, or posted to a publicly accessible website, in whole or in part.
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
FIGURE 5-7 Examples of correct uses of
external entities in a data flow diagram
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Keep in mind:
◦ All flow lines must
be labeled
◦ Large processes can
be broken down into
smaller components
FIGURE 5-9 Examples of correct and
incorrect uses of data flows
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Create a graphical model of the information
system based on your fact-finding results
◦ First, you will review a set of guidelines for
drawing DFDs
◦ Then you will learn how to apply these guidelines
and create a set of DFDs using a three-step
process
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Guidelines for Drawing DFDs
◦ 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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FIGURE 5-10 Context
diagram DFD for grading
system
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Step 1: Draw a
Context
Diagram
FIGURE 5-11 Context diagram DFD
for an order system
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Step 2: Draw a
Diagram 0 DFD
◦ If same data flows in
both directions, you can
use a double-headed
arrow
◦ Diagram 0 is an
exploded view of
process 0
◦ Parent diagram
◦ Child diagram
◦ Functional primitive
FIGURE 5-13 Diagram 0 DFD for the order system
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Step 3: Draw the
Lower Level
Diagrams
FIGURE 5-14 Diagram 1
DFD shows details of the
FILLORDER process in the
order system
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Must use leveling
and balancing
techniques
Leveling examples
◦ Uses a series of
increasingly detailed
DFDs to describe an
information
system
◦ Exploding,
partitioning, or
decomposing
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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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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or duplicated, or posted to a publicly accessible website, in whole or in part.
FIGURE 5-17 Example of a parent
DFD diagram, showing process 0 as a
black box
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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•
•
•
A data dictionary, or data repository, is a
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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Data element: Smallest piece of data that
has meaning within an information system
◦ Called data item or field
◦ Are combined into records, also called data
structures
Record: Meaningful combination of related
data elements that is included in a data flow
or retained in a data store
◦ Called data structures
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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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Documenting the Data Elements
◦ Every data element in the data dictionary should be
documented
◦ Objective – To provide clear, comprehensive
information about the data and processes that make
up a system
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Documenting the Data
Elements
◦
◦
◦
◦
◦
◦
◦
◦
◦
Data element name and label
Alias
Type and length
Default value
Acceptable values – Domain
and validity rules
Source
Security
Responsible user(s)
Description and comments
Source: Visible Systems Corporation.
FIGURE 5-20 A Visible Analyst screen describes
the data element named SOCIAL SECURITY
NUMBER.
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Documenting the Data Flows
◦
◦
◦
◦
◦
◦
◦
Data flow name or label
Description
Alternate name(s)
Origin
Destination
Record
Volume and frequency
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Documenting the Data
Stores
◦
◦
◦
◦
◦
Data store name or label
Description
Alternate name(s)
Attributes
Volume and frequency
Source: Visible Systems Corporation.
FIGURE 5-21 Visible Analyst screen that documents a
data store named IN STOCK
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Documenting the Processes
◦
◦
◦
◦
Process name or label
Description
Process number
Process description
FIGURE 5-22 Visible Analyst screen that describes a
process named VERIFY ORDER
Source: Visible Systems Corporation.
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Documenting the Entities – Data dictionary
describes all external entities that interact
with the system
◦ Characteristics include
Entity name
Description
Alternate name(s)
Input data flows
Output data flows
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Documenting
the Records
◦ Record or data
structure name
◦ Definition or
description
◦ Alternate name(s)
◦ Attributes
Source: Visible Systems Corporation.
FIGURE 5-23 Visible Analyst screen that documents a
record, or data structure named CREDIT STATUS
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Data Dictionary Reports – Following can be
obtained
◦ Alphabetized list of all data elements by name
◦ Report describing each data element and indicating
the user or department that is responsible for data
entry, updating, or deletion
◦ 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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or duplicated, or posted to a publicly accessible website, in whole or in part.
Process description: Documents the details of
a functional primitive and represents a specific
set of processing steps and business logic
Tools – structured English, decision tables, and
decision trees
Used in object-oriented development
◦ O-O analysis – combines data and the processes that
act on the data into things called objects, and similar
objects can be grouped together into classes
◦ O-O processes are called methods
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Modular Design
◦ Based on
combinations of
three logical
structures,
sometimes called
control structures,
which serve as
building blocks for
the process
Sequence
Selection
Iteration – looping
FIGURE 5-24 Sequence structure
FIGURE 5-25 Selection structure
FIGURE 5-26 Iteration
structure
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Structured English
◦ Rules
Use only the three building
blocks of sequence,
selection, and iteration
Use indentation for
readability
Use a limited vocabulary
standard terms used in the
data dictionary
Specific words that
describe the processing
rules
Source: Visible Systems Corporation.
FIGURE 5-27 The VERIFY ORDER process description
includes logical rules and a structured English version of
the policy. Notice the alignment and indentation of the
logic statements
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Decision Tables
◦ Show a logical structure, with all possible
combinations of conditions and resulting actions
Every possible outcome should be considered to
ensure that nothing has been overlooked
◦ Number of rules doubles each time a condition is
added
◦ Can have more than two possible outcomes
◦ Are the best way to describe a complex set of
conditions
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FIGURE 5-28 The Verify Order business process has two conditions. For an
order to be accepted, the product must be in stock and the customer must
have an acceptable credit status
FIGURE 5-29 Example of a simple decision table showing the processing logic of
the VERIFY ORDER process
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FIGURE 5-30 A third condition has been added to the Verify Order business process. For an order
to be accepted, the product must be in stock and the customer must have an acceptable credit
status. However, the credit manager now has the authority to waive the credit status requirement
FIGURE 5-31This table is based on the Verify Order conditions shown in Figure 5-30. With
three conditions, there are eight possible combinations, or rules
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FIGURE 5-32 In the first table, dashes have been added to indicate that a
condition is not relevant. In the second version, rules have been combined.
Notice that in final version, only four rules remain. These rules document the
logic, and will be transformed into program code when the system is developed
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FIGURE 5-33 A sales promotion policy with three conditions. Notice that the first statement contains
two separate conditions – one for the 5% discount, and another for the additional discount
FIGURE 5-34 This decision table is based on the sales promotion policy in
Figure 5-33. This is the initial version of the table, before simplification
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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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Decision Trees
◦ Graphical representation of the conditions, actions,
and rules found in a decision table
◦ Show the logic structure in a horizontal form that
resembles a tree
◦ Provide the same results as decision tables, but in
different forms
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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While structured analysis tools are used to
develop a logical model for a new information
system, such tools also can be used to
develop physical models of an information
system
A physical model shows how the system’s
requirements are implemented
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Sequence of Models
◦ Systems analysts create a physical model of
the current system and then develop a logical
model of the current system before tackling a
logical model of the new system
Performing extra step allows to understand the
current system better
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Four-Model Approach
◦ Develop:
A
A
A
A
physical model of the current system
logical model of the current system
logical model of the new system
physical model of the new system
◦ Disadvantage – Additional time and cost
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During data and process modeling, a systems
analyst develops graphical models to show
how the system transforms data into useful
information
The end product of data and process
modeling is a logical model that will support
business operations and meet user needs
Data and process modeling involves three
main tools: data flow diagrams, a data
dictionary, and process descriptions
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Data flow diagrams (DFDs) graphically show
the movement and transformation of data in
the information system
DFDs use four symbols
A set of DFDs is like a pyramid with the
context diagram at the top
The data dictionary is the central
documentation tool for structured analysis
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Each functional primitive process is
documented using structured English,
decision tables, and decision trees
Structured analysis tools can be used to
develop a logical model during one systems
analysis phase, and a physical model during
the systems design phase
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