Process Analysis I: Flow Charts, Decision Tables, Decision Trees

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Process Analysis I Flow Charts, Decision Tables,
Decision Trees

• Yale Braunstein
• School of Information Management Systems

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Processes

• These lectures all relate to processes
• Describing, analyzing, developing, modifying,
  documenting,
• Types of processes include
• Decision processes
• Data flow manipulation processes,
• Specific approaches depend on internal needs
  practices, standards
• A process model is a formal way of representing
  how a business operates

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Flow charts

• There are several standards just be consistent
• Manual methods vs. automated tools
• Visio, PowerPoint, etc.
• Waves of fashion / variety of uses
• Programming
• Documenting processes
• Multi-user settings
• General documentation of all sorts

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Flow chart techniques

• Basic symbols
• Terminator
• Process
• Decision
• Predefined process
• On-page connector
• Connector

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Flowchart guidelines

• Top to bottom, left to right on the page
• Activity being flowcharted should be defined
  carefully and made clear to reader
• Identity start and end
• Use one-verb (verb-noun) descriptions
• Examples prepare statement, file record
• Keep steps in proper sequence
• Observe scope range of activity branches
  should be on separate pages
• Use standard symbols lines should NOT cross
• Use cross-overs only if necessary keep lines
  straight
• No blind alleys or endless loops

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Samples (with comments)

• Dining room table (again)
• Only partially complete, has potentially endless
  loop
• Still partially complete, but with additional
  steps
• Flow of logic in an SPSS session
• No terminators, no decision points
• Flow of information in a survey
• No terminators, no decision points, but clear
  distinction betweens types of processes
• How to obtain your FBI file (or Elviss)
• Why you might want to do this (if time permits)

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Common problems

• Distinguish between do it and schedule it
• Avoid endless loops
• Account for follow-up on holds / pauses /
  unable to process conditions, etc.
• Make clear whether data flows and telecom links
  are one-way or two-way
• Do NOT link to processes use connectors

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Other uses for Visio

• Document spreadsheets
• Functional decomposition diagrams
• Network wiring diagrams
• E-R diagrams for databases
• Organization charts
• Statistical documentation output
• Crime scene documentation, time lines, etc.

Links to some of these are on the course download
page
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Decision tables Decision trees

• Sometimes DFDs and E-R diagrams do not work
  adequately or the nature of the problem is more
  analytic
• First, a slight digressionIt may help to
  specify the underlying logic in structured
  English
• Structured programming natural English
  Structured English

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Examples of Structured English - 1

• For each customer number in the customer table
• For each loan in the loans table that matches the
  above customer number
• Keep a running total of loans
• Keep a running total of the original loan
  principal
• Keep a running total of the current loan balance
• Keep a running total of the amounts past due

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Examples of Structured English - 2

• Sequence of Actions approach
• Action 1 Go to inventory area
• Action 2 present ID to guard
• Action 3 Pick items from stock
• Action 4 Wand the items

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Action Conditions can be simple or complex

• Simple Condition Actions
• If item is on shelf
• Then sequence of actions
• Else sequence of actions
• Complex Condition Actions
• Do the following based on the customer order
• Case 1 Construct turkey sandwich
• Case 2 Assemble taco salad
• Case 3 Construct pastrami sandwich

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Decision tables

• May be a better alternative to characterize the
  actions taken in a given task
• Tabular form of presentation that specifies a set
  of conditions and their corresponding actions
• Sometimes used for guidance in decision-making,
  especially if trying to routinize a process.

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Example Should we cash the check?

• Awful pun may go here
• We can document the process with a flow chart or
  with a decision table (or both)
• Which one is better?
• Depends on common practice in organization
• May depend on the specifics of the process
• The policy (decision rule)
• A customer with check-cashing privileges is
  entitled to cash personal checks up to 75 and
  payroll checks from pre-approved local employers.

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Construction of the decision table

• Four main parts
• Conditions vs. Actions
• Stub vs. Entry
• Conditions think of a series of if statements
• Actions think of a series of then statements

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General format
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The cash a check table
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Decision trees

• A decision tree is an alternate approach to
  representing decision situation
• More graphical
• Easier to change (sometimes)
• Shows conceptually what is going onyou step
  through the decision-making process

• Legend
• Salaried?
• Hours worked lt 40?
• Hours worked 40?