Technique 56

Cause & Effect Diagram

Investigate the root causes of performance problems.


A cause & effect (C&E) diagram enables you to brainstorm and categorize the variables that might be causing poor performance in your new process, product, service, or solution. Say you produce a high-tech oven that monitors the internal temperature of whatever you're cooking and tells you when the food is ready. If the oven occasionally misses the mark, you need to know whether the problem is with the temperature gauge, the humidity sensor, the notification system, or the food itself. A C&E diagram helps you determine the root cause of the problem (output) by systematically identifying all the potential causes (inputs).

If your innovation isn't performing as expected or specified, or if you want to anticipate what could go wrong with your design before going into production, you can use a C&E diagram. Just make sure that your team is knowledgeable about the system or process in question, and that they're open to getting to the root cause of any issues.

Process Capability (Technique 41) is the metric by which you know if you are having any performance issues or defect problems to solve. Once you use process capability to determine this, you then use a cause & effect diagram to start analyzing the problem.


Scenario: Let's say you have a new service that rents DVD movies to customers through the mail. Recently, you've detected a decrease in customer satisfaction and retention. Using ...

Get The Innovator's Toolkit: 50+ Techniques for Predictable and Sustainable Organic Growth, 2nd Edition now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.