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

1. Process Analysis I: Flow Charts, Decision Tables, Decision Trees Yale Braunstein School of Information Management & Systems

2. 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”

3. 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

4. Flow chart techniques • Basic symbols • Terminator • Process • Decision • Predefined process • On-page connector • Connector

5. 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

6. 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 Elvis’s) • Why you might want to do this (if time permits)

7. 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

8. 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

9. 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 digression:It may help to specify the underlying logic in “structured English” • Structured programming + natural English = Structured English

10. 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

11. 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

12. 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

13. 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.

14. 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.”

15. 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

16. General format

17. The “cash a check” table

18. Decision trees • A decision tree is an alternate approach to representing decision situation • More graphical • Easier to change (sometimes) • Shows conceptually what is going on—you step through the decision-making process • Legend: • Salaried? • Hours worked < 40? • Hours worked = 40?