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

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

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

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

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

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)

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

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

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

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

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

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

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.

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.”

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

General format

The “cash a check” table

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?