Logical Flow
A logical flow diagram maps the decision-making steps of a system, supplementing the functional analysis. FFBDs show how the system works functionally; a logical flowchart helps to identify where decisions are made and what inputs are required.
Example applications
Logical flow diagrams are essentially decision trees: do this step, if A happens do B, if C happens do D, else E. Logical flow diagrams are commonly used to show business processes, such as processing an online order, or mapping out a call centre complaints procedure. A flowchart can be broken into users, hardware, resources or systems to highlight the roles and actors in a process (see p108 of Hurt, 2012).
Similar to…
The logical flow and functional flows are very similar, but focus on two different things. A logical flow emphasises the decisions and resulting actions of a process, whereas a functional flow describes a manual-style procedure that should be followed.
Steps
A good logical flowchart should help the user understand the logical progression of the required steps to follow in a process. A comprehensive flow chart will have all of the contingencies clearly covered.
- Establish the start and finish points of the process that you’re mapping. Scope the system boundary to a useful level.
- Determine column headings. These could be systems, users that interact with the system, or different plant/machines that are required.
- List the required actions for each column, and where the interactions between columns occur
- Seek feedback, discuss and revise
Hints
- you should be able to read a flowchart from left-to-right, top-to-bottom. Give your flowchart a title, and don’t cram everything in. Position the flowchart at a useful level within the system - too detailed and it will become too difficult to use, and too high-level and it will become trivial
- organising your flowchart in columns by responsibility or resource can help to identify issues in your processes
- get feedback on preliminary flowcharts from stakeholders before delving into detail
Core resources
- Hurt, R., 2012, Accounting Information Systems, Chapter 6 [PDF]
- The Ultimate Flowchart Guide - on Creately, and informal but informative source [Website]
- Classic engineering case study: WD40 or Tape [Image]
Software
Choosing the right software for flowcharts and other diagrams can make a big visual impact. Gliffy is popular online service, and Omnigraffle is my favourite on a Mac. Visio is the Windows-standard. Avoid using diagramming tools in a word processor - they almost always look second-rate.