The Senate Finance and House Ways and Means Committees held a joint hearing on the impact on the economy of taxation of business and individual debt.   Witnesses: • Thomas A. Barthold, chief of staff, Joint Committee on Taxation • Mihir A. Desai, professor of finance, Harvard Business School • Pamela F. Olson, partner, Skadden, Arps, Slate, Meagher & Flom, and former assistant secretary of the Treasury for tax policy • Victor Fleischer, associate professor of law, University of Colorado Law School • Simon Johnson, professor of entrepreneurship, Sloan School of Management, Massachusetts Institute of Technology, and former economic counsellor and director, Research Department, International Monetary Fund