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.[1]: 47
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.[2]
According to professor of strategy Arnaud Chevallier, elaborating an approach used at McKinsey & Company,[3] there are two types of issue trees: diagnostic ones and solution ones.[4] 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.[5]
Issue trees are used to answer questions in case interviews for management consulting positions.[7] A quantitative type of question, the market sizing question, requires 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.[8] The candidates are expected to use a structured and logical method of arriving at their answer, and using an issue tree provides a diagram to aid the candidate's logical reasoning. Issue trees are used for other types of case interview questions as well.[7]
^See also the how–why diagrams in: 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. ISBN9781462058549. OCLC767703320.
^ abCheng, Victor (2012). "The issue tree". Case interview secrets: a former McKinsey interviewer reveals how to get multiple job offers in consulting. Seattle, WA: Innovation Press. pp. 73–102. ISBN9780984183524. OCLC803397971.
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.