His primary research interests lie in the areas of information theory and communications, particularly coding and modulation techniques, with applications to digital data storage and transmission.

Prof. Siegel was a member of the Board of Governors of the IEEE Information Theory Society from 1991 to 1996 and from 2009 to 2014. He served as Co-Guest Editor of the May 1991 Special Issue on “Coding for Storage Devices” of the IEEE Transactions on Information Theory. He served the same Transactions as Associate Editor for Coding Techniques from 1992 to 1995, and as Editor-in-Chief from July 2001 to July 2004. He was also Co-Guest Editor of the May/September 2001 two-part issue on “The Turbo Principle: From Theory to Practice” and the February 2016 issue on “Recent Advances in Capacity Approaching Codes” of the IEEE Journal on Selected Areas in Communications.