We are pleased to announce the launch of the Large Scale Hierarchical Text classification  (LSHTC) Pascal Challenge. The LSHTC Challenge is a hierarchical text classification competition using large datasets based on the ODP Web directory data (www.dmoz.org).

Hierarchies are becoming ever more popular for the organization of text documents, particularly on the Web. Web directories are an example. Along with their widespread use, comes the need for automated classification of new documents to the categories in the hierarchy. As the size of the hierarchy grows and the number of documents to be classified increases, a number of interesting machine learning problems arise. In particular, it is one of the rare situations where data sparsity remains an issue despite the vastness of available data. The reasons for this are the simultaneous increase in the number of classes and their hierarchical organization. The latter leads to a very high imbalance between the classes at different levels of the hierarchy. Additionally, the statistical dependence of the classes poses challenges and opportunities for the learning methods.

The challenge will consist of four tasks with partially overlapping data. Information regarding the tasks and the challenge rules can be found at the “Tasks, Rules and Guidelines” link.

We plan a two-stage evaluation of the participating methods: one measuring classification performance and one computational performance. It is important to measure both, as they are dependent. The results will be included in a final report about the challenge and we also aim at organizing a special workshop.

In order to register for the challenge and gain access to the datasets, please create a new account at http://lshtc.iit.demokritos.gr/.


Eric Gaussier, LIG, Grenoble, France
George Paliouras, NCSR “Demokritos” , Athens, Greece
Aris Kosmopoulos, NCSR “Demokritos” and AUEB, Athens, Greece
Sujeevan Aseervatham, LIG, Grenoble, France