Process Analysis I Flow Charts Decision Tables Decision

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

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 2

Flow charts • There are several standards – just be consistent • Manual methods vs. automated tools – Visio, Power. Point, etc. • Waves of fashion / variety of uses – Programming – Documenting processes – Multi-user settings – General documentation of all sorts 3

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

Flowchart guidelines 1. Top to bottom, left to right on the page 2. Activity being flowcharted should be defined carefully and made clear to reader 3. Identity start and end 4. Use “one-verb” (verb-noun) descriptions – Examples: “prepare statement, ” “file record” 5. Keep steps in proper sequence 6. Observe scope & range of activity; branches should be on separate pages 7. Use standard symbols; lines should NOT cross – Use cross-overs only if necessary; keep lines straight 8. No blind alleys or endless loops 5

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) 6

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 7

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, etc. Links to some of these are on the course download page 8

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 9

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 1. 2. 3. 4. 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 10

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 11

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 12

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 decisionmaking, especially if trying to routinize a process. 13

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. ” 14

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 15

General format 16

The “cash a check” table 17

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 decisionmaking process Legend: 1) Salaried? 2) Hours worked < 40? 3) Hours worked = 40? 18