He received his PhD from the University of California at Berkeley. His research interests include reducing the costs associated with software development (particularly through automated program repair) as well as program analysis, formal verification, and human linguistic and visual interaction with software. He is a senior member of the Association for Computing Machinery and his work has led over eight thousand citations and several awards, including two ‘Humies’ for his work on using Genetic Improvement for bug fixing. He also organised the second Genetic Improvement Workshops.