He is the director of the Center for Machine Learning and Language Processing, one of the six centers of the Human Language Technology Research Institute at UT Dallas. His primary research is in the area of machine learning of natural language, where his goal is to develop and apply machine learning techniques to the construction of robust and portable natural language processing (NLP) systems. While he is best known in the NLP community as an expert on information extraction and coreference resolution, his research has spanned a wide range of topics in NLP, ranging from low-level tasks such as morphology and part-of-speech tagging to high-level NLP applications such as text classification and automated essay grading.