This case is related to Chapter 10, Cause-and-Effect (Ishikawa) Diagrams.
The scope of the case is the security check area in an airport terminal. Through the security check, passengers’ ID’s are checked and then passengers and their belongings go through metal detector machines.
The terminal suffers congestion in the security check area, and passengers are complaining about the long time it takes to go through security.
You are assigned to investigate the situation. In the first step of your analysis, you need to draw a cause-and-effect (fishbone or Ishikawa) diagram that entails all factors and possible causes that can potentially impact and contribute to the problem.
Note that your task in this case is not to find the main cause(s) of the problem as this needs data gathering and analyzing the real situation.