John Maindonald, Australian National University Data Mining - Statistics Without Statistical Theory? Abstract The tradition of Data Mining arose from the computing community. It is in part a response to the power of modern computational systems to the new opportunities for collecting and collating data, to new types of data (images, web pages, genomic data, ...) that are available to those who have the skills to work with them, and to algorithms that have attracted a particular following in the data mining community. Data Mining has had also, elements of an attempt to invent a new tradition of statistical analysis. A number of departments, including some statistics departments, are now offering courses in data mining. I will argue that this activity has been too often compromised by inadequate attention to insights that have been teased out within the statistical tradition. At the same time, new perpectives, and a challenge to rethink some aspects of common statistical practice, can be a useful source of invigoration. Many of the problems tackled in the data mining literature have novel and interesting features, and may be tackled using models with which many or most statisticians are unfamiliar. I will o er an assessment of key issues where effective dialogue is required between the data mining and the statistical traditions.