Issue tree

An issue tree showing how a company can increase profitability: A profitability tree is an example of an issue tree. It looks at different ways in which a company can increase its profitability. Starting from the key question on the left, it breaks it down between revenues and costs, and break these down into further details.

An issue tree, also called logic tree, is a graphical breakdown of a question that dissects it into its different components vertically and that progresses into details as it reads to the right.

Issue trees are useful in problem solving to identify the root causes of a problem as well as to identify its potential solutions. They also provide a reference point to see how each piece fits into the whole picture of a problem.

According to professor of strategy Arnaud Chevallier, there are two types of issue trees: diagnostic ones and solution ones.

Diagnostic trees break down a "why" key question, identifying all the possible root causes for the problem. Solution trees break down a "how" key question, identifying all the possible alternatives to fix the problem.

Four basic rules can help ensure that issue trees are optimal, according to Chevallier:

1. Consistently answer a "why" or a "how" question
2. Progress from the key question to the analysis as it moves to the right
3. Have branches that are mutually exclusive and collectively exhaustive (MECE)
4. Use an insightful breakdown

The requirement for issue trees to be collectively exhaustive implies that divergent thinking is a critical skill.

See also

• Five whys
• Ishikawa diagram
• Issue map
• Root cause analysis
• Why–because analysis

Issue trees in interviews

Issue trees are commonly used to answer market sizing (also known as guesstimate) interview questions. These are questions that require the interviewee to estimate the size of a data group such as a specific segment of a population, an amount of objects, a company's revenues, or similar. The candidates are expected to use a structured and logical method of arriving at their answer and using an issue tree provides a physical diagram to aid the candidates logical reasoning to the interviewer.

Examples of the types of interview questions that may benefit from an issue tree are:

• How many people own a dog in India?
• How many passengers pass through Dubai airport each year?
• What is the size of the Australian hairdryer market?

Further reading

• Chevallier, Arnaud (11 April 2011). "Don't get lost in the terminology". powerful-problem-solving.com. Retrieved 2018-10-06. Issue trees, issue maps, logic trees, how trees, why trees, diagnostic trees, solution trees, decision trees, fact trees, hypothesis trees... How should you call your trees?... Call your tree what you want it to do. {{cite web}}: Invalid |ref=harv (help)
• Chevallier, Arnaud (19 February 2011). "Use your issue tree as a decision tree". powerful-problem-solving.com. Retrieved 2018-10-06. {{cite web}}: Invalid |ref=harv (help)
• Culmsee, Paul; Awati, Kailash (2013) [2011]. "Visualising complexity". The heretic's guide to best practices: the reality of managing complex problems in organisations. Bloomington: iUniverse, Inc. pp. 159–167. ISBN 9781462058549. OCLC 767703320. {{cite book}}: Invalid |ref=harv (help)