Editing Decision tree learning (section)

{{short description|Machine learning algorithm}}
{{about|decision trees in machine learning|the use of the term in decision analysis|Decision tree}}
{{Machine learning|Supervised learning}}

'''Decision tree learning''' is a [[supervised learning]] approach used in [[statistics]], [[data mining]] and [[machine learning]]. In this formalism, a classification or regression [[decision tree]] is used as a [[predictive model]] to draw conclusions about a set of observations.

Tree models where the target variable can take a discrete set of values are called '''[[Statistical classification|classification]] [[decision tree|trees]]'''; in these tree structures, [[leaf node|leaves]] represent class labels and branches represent [[Logical conjunction|conjunction]]s of features that lead to those class labels. Decision trees where the target variable can take continuous values (typically [[real numbers]]) are called '''[[regression analysis|regression]] [[decision tree|trees]]'''. More generally, the concept of regression tree can be extended to any kind of object equipped with pairwise dissimilarities such as categorical sequences.<ref name=":1">{{Cite journal |last1=Studer |first1=Matthias |last2=Ritschard |first2=Gilbert |last3=Gabadinho |first3=Alexis |last4=Müller |first4=Nicolas S. |date=2011 |title=Discrepancy Analysis of State Sequences |url=http://journals.sagepub.com/doi/10.1177/0049124111415372 |journal=Sociological Methods & Research |language=en |volume=40 |issue=3 |pages=471–510 |doi=10.1177/0049124111415372 |s2cid=13307797 |issn=0049-1241}}</ref>

Decision trees are among the most popular machine learning algorithms given their intelligibility and simplicity because they produce models that are easy to interpret and visualize, even for users without a statistical background.<ref>{{Cite journal|last1=Wu|first1=Xindong|last2=Kumar|first2=Vipin|last3=Ross Quinlan|first3=J.|last4=Ghosh|first4=Joydeep|last5=Yang|first5=Qiang|last6=Motoda|first6=Hiroshi|last7=McLachlan|first7=Geoffrey J.|last8=Ng|first8=Angus|last9=Liu|first9=Bing|last10=Yu|first10=Philip S.|last11=Zhou|first11=Zhi-Hua|date=2008-01-01|title=Top 10 algorithms in data mining|journal=Knowledge and Information Systems|language=en|volume=14|issue=1|pages=1–37|doi=10.1007/s10115-007-0114-2|s2cid=2367747|issn=0219-3116|hdl=10983/15329|hdl-access=free}}</ref>

In decision analysis, a decision tree can be used to visually and explicitly represent decisions and [[decision making]]. In [[data mining]], a decision tree describes data (but the resulting classification tree can be an input for decision making).