Reference Work Entry

Encyclopedia of Database Systems

pp 988-991


  • Zhi-Hua ZhouAffiliated withNanjing University


Committee-based learning; Multiple classifier system; Classifier combination


Ensemble is a machine learning paradigm where multiple learners are trained to solve the same problem. In contrast to ordinary machine learning approaches which try to learn one hypothesis from training data, ensemble methods try to construct a set of hypotheses and combine them.

Historical Background

It is difficult to trace the starting point of the history of ensemble methods since the basic idea of deploying multiple models has been in use for a long time. However, it is clear that the hot wave of research on ensemble methods since the 1990s owes much to two works. The first is an applied research conducted by Hansen and Salamon at the end of 1980s [5], where they found that predictions made by the combination of a set of neural networks are often more accurate than predictions made by the best single neural network. The second is a theoretical research ...

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