Making CN 2 - SD subgroup discovery algorithm scalable to large size data sets using instance selection q

The subgroup discovery, domain of application of CN2-SD, is defined as: ‘‘given a population of individuals and a property of those individuals, we are interested in finding a population of subgroups as large as possible and have the most unusual statistical characteristic with respect to the property of interest’’. The subgroup discovery algorithm CN2-SD, based on a separate and conquer strategy, has to face the scaling problem which appears in the evaluation of large size data sets. To avoid this problem, in this paper we propose the use of instance selection algorithms for scaling down the data sets before the subgroup discovery task. The results show that CN2-SD can be executed on large data set sizes pre-processed, maintaining and improving the quality of the subgroups discovered. 2007 Elsevier Ltd. All rights reserved.