Many case studies have shown that decision trees are at least as accurate as human experts. For example, one study for diagnosing breast cancer had humans correctly classifying the examples 65% of the time, and the decision tree classified 72% correct.

British Petroleum designed a decision tree for gas-oil separation for offshore oil platforms, that replaced a rule-based expert system.

Cessna designed an airplane flight controller using 90,000 examples and 20 attributes per example.